Fix _Rendezvous.exception for successful calls

Change port_server.py to use port 32766

Bumped grpc-tools version

Use open-source defaults to propagate Python plugin configuration

32767 is used by filenet-powsrm

PHP: fix shutdown hang issue

Make handlers optional at server construction

Small C# docs improvements

Update C# examples to 0.15.0 packages.

Fix clang formatting

fix building ruby package

Update version to 0.15.0

Allow Node users to set a custom logger and log verbosity.

Doc Fixit: Ordering and thread-safety for C++ streaming (sync/async) APIs

Fix C# nuget build (and all distribtests)

Fix build node package

Prevent race with grpc_completion_queue_shutdown.

Use GRPC_PYTHON_CFLAGS/GRPC_PYTHON_LDFLAGS in setup.py.

Changed %lld to use mingw supported PRId64

Brought compression spec up to date wrt error statuses

This is needed for building grpcio with mingw, see
https://github.com/grpc/grpc/pull/7012.

Remove generated NewClient factory method for C#.