Cleanup LICENSE file.

Add kokoro build status badges.

Moved the badges to the language table as they are per-language based.
Some badges are not yet available due to stuck kokoro jobs.

Delete unused directories.

jenkins has been replaced by kokoro and we never use more_tests.

Removed atomicops.h stub

Change C# reflection to avoid using expression trees

For oneofs, to get the case, we need to call the property that
returns the enum value. We really want it as an int, and modern
runtimes allow us to create a delegate which returns an int from the
method. (I suspect that the MS runtime has always allowed that.)
Old versions of Mono (e.g. used by Unity3d) don't allow that, so we
have to convert the enum value to an int via boxing. It's ugly, but
it should work.

This should work on Unity, Mono and .NET 3.5 as far as I'm aware.
It won't work on platforms where reflection itself is prohibited,
but that's a non-starter basically.

Delete javanano kokoro build configs.

Remove broken build status icons.

Remove copyright attributions to files that no longer exist; Change the
year to 2008 to be consistent with the copyright header of other source
files.

Their job configs are being deleted in cl/190526138

Add googletest as a submodule in third_party/googletest.

* when interpreting options, rewrite file descriptor's source code info
- so that interpreted option paths have correct location information
- so that corresponding uninterpreted option paths are removed
also includes a fix to source code locations for extension range options

Remove javanano.

Fix bug: whether always_print_enums_as_ints is true or false, it alwa…

Fix missing LIBPROTOC_EXPORT.

This makes possible to build grpc_php_plugin with protobuf in shared mode.

Don't assume Windows builds use MSVC.

Updated Ruby conformance test failure list

Added missing .inc files to BUILD

This commit adds two entries to the conformance failure list for Ruby.
It seems that these particular test cases have been failing since they
were introduced in 5140bae3, so there
has not been any regression.

This fixes the Bazel build.

Add performance.md and add instruction for linking tcmalloc

Removed some unused C++ source files

Switch to using the MSVC options, not based on the cpu, but based
on the compiler name. This allows building on Windows with MSYS
or MinGW's gcc.

Integrated internal changes from Google