We now do this in protoc instead of the generation simpler.

Benefits:
- Generation script is simpler
- Detection is simpler as we now only need to care about one filename
- The embedded descriptor knows itself as "google/protobuf/descriptor.proto" avoiding dependency issues

This PR also makes the "invalid dependency" exception clearer in terms of expected and actual dependencies.

Fix bugs on windows

Update cmake and BUILD files.

Change-Id: I17e16fdae6e4d2fb74d178fa5564a609ed58af1d

Change-Id: I74a73d3135ec1e0e4d52d741a77456b8e55f038f

Change-Id: I83a93fdb119a643fbc884e6ec3624493f6270370

(cherry-picking an intenral change).

Manually merge pull request: https://github.com/google/protobuf/pull/674
that fixes the gcc C++11 build.

Change-Id: If3fb07754a734bae610d95124528e073515ac525

Change-Id: Ieb7a2c2fbf35bc2a8fa65b915a5ecb68c83863e4

Ruby: Conform to C89/C90 variable declaration rules.

Change-Id: I6cf77f01370204ad4bc7b345a040a9a3de1706a0

C# fix for TypeInitializer exception.

Add support for a file listing expected package to objc prefixes for validation.

- Add a env var to pass a set of expected prefixes for validation.
- Report warnings/errors based on the expected prefixes vs. the data in the files compiled.
- Use some helpers from common directory.

Fixed several Ruby conformance test cases through upb update.

Allow public access to descriptor.proto as a dependency.

With this in place, generating APIs on github.com/google/googleapis works - previously annotations.proto failed.
Currently there's no access to the annotations (stored as extensions) but we could potentially expose those at a later date.

Install protobuf from cmake project

Change-Id: Ief77de7134e05e07b1a7e3970d49880c2d5e6fe9

Link runtime statically for VS build

Revert "Add packFrom, unpackTo and is in google.protobuf.Any."

This reverts commit 7366efd8.

Still some discussion about the api to expose the helpers with.

Update GPBWellKnownTypes.m

More TODOs done.

- Removed a TODO without change in DescriptorPool.LookupSymbol - the TODOs were around performance, and this is only used during descriptor initialization
- Make the CodedInputStream limits read-only, adding a static factory method for the rare cases when this is useful
- Extracted IDeepCloneable into its own file.

Implement Keys and Values as views in MapField

 Make FieldDescriptor.IsPacked work appropriately.