Only keep docker containers for tests that failed

Add Connectivity doc

fetch PR refspec for docker jenkins builds

Fix native callback signature to match with C#

Speed up hash checks, crash on first TSAN error

Revamp of C# channel options (aka channel args)

Stability fixes for python_plugin_test

The "normal" timeout is eliminated. The "short" timeout is changed to
be the length used in tests that will time out as part of their
execution and the "long" timeout is changed to be a ridiculously high
value that will have no bearing on passing tests.

The "pause" behavior of _ServicerMethods is changed to use a
threading.Condition's wait/notify methods rather than busy-sleeping.

Tests that used servicer delay to verify that asynchronous calls are
not affected by server delay are changed to use servicer pause to
verify that asynchronous calls return while the servicer is paused.

Busy-sleeping in testHalfDuplexCallWedged is replaced with use of a
threading.Condition's wait/notify methods.

Fixes https://github.com/grpc/grpc/issues/1900.

Ensure C89 compatibility in Linux tests.

update PHP README installation instructions

Flagging unused parameters as unused.

Update README.rst

Cosmetic tweaks to python_plugin_test.py.

Update src/python/README.md to link to quick
start and detailed example documentation.

Tiny comment fix

Make async server use one CQ per server thread

add missed explicit

Removed leftover TODO

No behavioral changes. Changes to comments are error correction, not
changes of specification.

Fix minor bug GRPC_TIMER_END before end of function

Upgrade protobuf version used by gRPC Python to 3.0.0a3 and
update version number of gRPC Python to 0.9.0a1.