* uses namespaces for nested messages and enums

* fixes namespaces for PHP dist

* fixes namespace for Descriptors, adds Cardinality and Kind

* fixes nested namespaces for reserved words and adds tests

* adds tests and generator fix for php class prefixes

* fixes escaping of protobuf packages, enum comments, misc others

* nice refactor of generated code

* adds class files for backwards compatibility

* simplifies code with templates

* adds compatibility files to makefile

* cleanup of generator and fixes nested namespace bug

* regenerates proto types

* remove internal BC classes

* adds deprecated warning, adds methods back

* simplifies if statement

* fixes dist files

* addresses review comments

* adds back TYPE_URL_PREFIX constant

* adds @deprecated to old nested class files

* skips tests which require a separate process when protobuf.so is enabled

* Adds tests for legacy nested classes that do not require separate processes to test

* uses legacy names for GPBUtil message check

* adds block for IDE @deprecated message

* Namespace for nested message/enum in c extension

* Remove unused code

* uses namespaces for nested messages and enums

* fixes namespaces for PHP dist

* fixes namespace for Descriptors, adds Cardinality and Kind

* fixes nested namespaces for reserved words and adds tests

* adds tests and generator fix for php class prefixes

* fixes escaping of protobuf packages, enum comments, misc others

* nice refactor of generated code

* adds class files for backwards compatibility

* simplifies code with templates

* adds compatibility files to makefile

* cleanup of generator and fixes nested namespace bug

* regenerates proto types

* remove internal BC classes

* adds deprecated warning, adds methods back

* simplifies if statement

* fixes dist files

* addresses review comments

* adds back TYPE_URL_PREFIX constant

* adds @deprecated to old nested class files

* skips tests which require a separate process when protobuf.so is enabled

* Adds tests for legacy nested classes that do not require separate processes to test

* uses legacy names for GPBUtil message check

* adds block for IDE @deprecated message

* Namespace for nested message/enum in c extension

* Remove unused code

* Add well known types to php runtime.

* Fix php7.0 tests

* No longer generate empty.proto in test as it has been included in
runtime.

* Fix zts build

* Clean code

* Rename g_p_b_empty to empty.

* Don't generate code for empty.proto in compatibility test

* Fix 32-bit

* Fix mac build

* Fix Makefile.am to add new files

- Capture the version used to generated.
- Check at compile time and runtime that generated code isn't from a newer
  version, also check that the min version required is also supported.
- Keep the old constants/macros/functions to special case the last version
  that was working so those generated sources still work until we decide
  otherwise.

- Capture the ObjC prefix used when generating the the file.
- Track the containing type on descriptors.
- Mark descriptors where the message class name got a suffix added to it.
- Expose a fullName property on Descriptors.
- Add helpers for packing/unpacking Any messages.
- Bump the ObjC runtime version number. Since we added methods and invoke them
  in the generated code, ensure the code is running against a matching version.
  Otherwise, someone could compile against headers, but run with a framework
  that is older and get unknown selector failures.  This should trip clearer
  messaging.

Fixes https://github.com/google/protobuf/issues/1674

Fixes extra whitespace on generated comments.

Convert mapping of proto comments to appledoc format so they show up in Xcode and cocoadocs.

Fixes https://github.com/google/protobuf/issues/1866

Fixes extra whitespace on generated comments.

Convert mapping of proto comments to appledoc format so they show up in Xcode and cocoadocs.

Fixes https://github.com/google/protobuf/issues/1866

1. Add missing header file to Makefile.am.
2. Re-generate objectivec generated code for well-known types.

Change-Id: If28217c701cf8bd739ea0db240e9eee600f23ee7

- Add generator constant for the default framework name.
- Add generator api for making the CPP symbol from the name.
- Add generator api to see if it is a bundled proto file.
- Output a CPP conditional and two imports for the core library headers.
- Add helper for generating the #import for file headers to deal with the
  framework imports.
- Add a reference from the unittests to a WKT to use that to inspect how
  imports generate.
- Update the podspec to define the CPP symbol and require pods 1.0 (or later).

Fixes https://github.com/google/protobuf/issues/1457

NOTE: This is a binary breaking change as structure sizes have changed size
and/or order.

- Drop capturing field options, no other options were captured and other mobile
  targeted languages don't try to capture this sort information (saved 8
  bytes for every field defined (in static data and again in field descriptor
  instance size data).
- No longer generate/compile in the messages/enums in descriptor.proto. If
  developers need it, they should generate it and compile it in. Reduced the
  overhead of the core library.
- Compute the number of has_bits actually needs to avoid over reserving.
- Let the boolean single fields store via a has_bit to avoid storage, makes
  the common cases of the instance size smaller.
- Reorder some flags and down size the enums to contain the bits needed.
- Reorder the items in the structures to manually ensure they are are packed
  better (especially when generating 64bit code - 8 bytes for every field,
  16 bytes for every extension, instance sizes 8 bytes also).
- Split off the structure initialization so when the default is zero, the
  generated static storage doesn't need to reserve the space. This is batched
  at the message level, so all the fields for the message have to have zero
  defaults to get the saves. By definition all proto3 syntax  files fall into
  this case but it also saves space for the proto2 that use the standard
  defaults. (saves 8 bytes of static data for every field that had a zero
  default)
- Don't track the enums defined by a message. Nothing in the runtime needs it
  and it was just generation and runtime overhead. (saves 8 bytes per enum)
- Ensure EnumDescriptors are started up threadsafe in all cases.
- Split some of the Descriptor initialization into multiple methods so the
  generated code isn't padded with lots of zero/nil args.
- Change how oneof info is feed to the runtime enabling us to generate less
  static data (8 bytes saved per oneof for 64bit).
- Change how enum value informat is capture to pack the data and only decode
  it if it ends up being needed. Avoids padding issues causing bloat of 64bit,
  and removes the needs for extra pointers in addition to the data (just the
  data and one pointer now).

- Convert most of the core library headers over to HeaderDoc format.
- Switch the generated comments over to HeaderDoc.
- Create GPBCodedOutputStream_PackagePrivate and move some things into there
  that should be more internal.

- Extend GPB*ObjectDictionary to support generic syntax.
- Update the generator to output generics so the enclosed type is exposed for compiler checks.
- Use generics in a the public interfaces.
- Update the generated sources that are checked in.

Add the clang annotations to the objc library and generated code to help with Swift bridging and compiler checks.

- Add more to the ObjC dir readme.
- Merge the ExtensionField and ExtensionDescriptor to reduce overhead.
- Fix an initialization race.
- Clean up the Xcode schemes.
- Remove the class/enum filter.
- Remove some forced inline that were bloating things without proof of performance wins.
- Rename some internal types to avoid conflicts with the well know types protos.
- Drop the use of ApplyFunctions to the compiler/optimizer can do what it wants.
- Better document some possible future improvements.
- Add missing support for parsing repeated primitive fields in packed or unpacked forms.
- Improve -hash.
- Add *Count for repeated and map<> fields to avoid auto create when checking for them being set.

- Style fixups in the code.
- map<> serialization fixes and more tests.
- Autocreation of map<> fields (to match repeated fields).
- @@protoc_insertion_point(global_scope|imports).
- Fixup proto2 syntax extension support.
- Move all startup code to +initialize so it happen on class usage and not app startup.
- Have generated headers use forward declarations and move imports into generated code, reduces what is need at compile time to speed up compiled and avoid pointless rippling of rebuilds.