Introduce a new nuget package, Google.Protobuf.Tools, basically to contain protoc on multiple platforms.

Added an API to allow oversize protos when using C++ extension in Python

Replace #include <iostream> with #include <ostream> in int128.cc

Introduce a new nuget package, Google.Protobuf.Tools, basically to contain protoc on multiple platforms.

I've moved both protoc.exe and the proto files out of Google.Protobuf.
The .proto files aren't a slam-dunk, but it feels like they belong with protoc as you'd *use* them with protoc.
It's not clear to me whether we really need both an x86 and x64 version of protoc.exe, as x86 would work on 64-bit Windows anyway. Discuss :)

Refactoring of FieldDescriptor

iostream is not actually necessary here, and it introduces unnecessary
static initializers.

Use the T() instead of NULL for the default value.

Add support for running on Jenkins

This makes no externally visible behavioral changes. Internally and non-behaviorally:

- We use a field (compiler-generated) to store the JsonName to avoid recomputing it repeatedly
- The documentation for JsonName is updated to reflect the meaning better
- Readonly autoprops and expression-bodied properties used where possible

csharp: add support for the json_name option

The template can be specialized on primitives, e.g. double, where
converting NULL will trigger a warning.

Mark iOS tests as able to fail.

Travis updated their images to include an xctool that can randomly kill
tests, so mark them as flaky to avoid turning things red.

The message was autoreleased, the -releases are an over release.

export well known protos

Update coded_stream.h

fix warning treated as error prevents building on 64-bit windows.

Allow custom URLs for Any in JsonFormat

Only create the readonlySemaphore on demand.

This will lower the amount of dispatch_semaphores created per Message when the
full object tree isn't walked in a way that would require them to be created.
Uses a dispatch_once_t for one time init of the dispatch_semaphore.

- Using custom URL for types in Any will no longer throw an
InvalidProtocolBufferException in JsonFormat
- Fixes #1128

Conflicts:
	csharp/src/Google.Protobuf/JsonFormatter.cs

Shrink ObjC overhead (generated size and some runtime sizes)

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).

add java/util support based on java/util/pom.xml

Adds more information to Objective C error.

Bazel iOS build settings

pass correct args to protoc for wellknown protos when used as an external repository

Fixing compilation error when building with emscripten.

This change was previously done in //third_party in CL 108656107 but never made it to the open source project and was overwritten in an update.