Fixes #4060

Fix file permission for python package.

`umask 0022` makes sure the created package will be accessible by all users.

Java: generate an annotation to suppress deprecation warnings

Add deprecation annotation for oneof case.

The valueOf method on enums is deprecated, but for compatibility reasons
the generated code has to keep using it. We can use an annotation to
suppress the deprecation warnings.

* Add auto-generated header to C# generated files

* regenerate C# protos

 Avoid double underscores in macro name

Added our standard license header to structurally_valid.cc and its test

 Add unknown field support for csharp

Fixes https://github.com/google/protobuf/issues/3268

Clarify default value behavior in JSON conversion.

This fixes issue #1775.

Update comments for Timestamp JSON format.

fix undefined behavior in C++03

Make //:protobuf_python have correct __init__.py.

Make it clear default value is only omitted for proto3.

Clarify that JSON parser are required to accept both UTC and other
timezone offsets.

Fixes issue 3093

With this in place, all tests should pass.

Fixes #3725.

This is the manual code part of the Google.Protobuf library, and tests.
Some tests will fail until codegen is changed and rerun.

--pre is not necessary

Using binary one's complement to negate an unsigned int

Ran update_file_lists.sh to update Bazel and CMake file lists

Use the portable version of Log2Floor for Clang with older Android NDK versions

This is necessary for avoiding a strange compiler error that we have
already run into with older versions of Clang on NaCl.

This should fix Bazel builds, since those were missing a new file
(implicit_weak_message.cc).

This removes a Visual Studio warning:

warning C4146: unary minus operator applied to unsigned type, result
still unsigned.

--pre was not necessary to install google-protobuf when I tried it today (2017-12-06).

Integrated internal changes from Google

Sync benchmark changes from internal