Release Python 0.5.0a2

Extern-ify symbols to avoid collision.

Fix errant empty data frame after trailers

Integration of Systemtap as a profiling mechanism.

Remove dbg build from Travis, use gcov instead

Release Python 0.5.0a1

Php auth interop test

With the metadata batching changes recently, I introduced a bug whereby
the http2 stream encoder would end up not being able to set the close bit on a header frame, and instead placed it on a new data frame, which is illegal by the HTTP2 spec.

Exposed server address string in stub

make initializing overlapped-struct obvious for preventing a ciritical bug

Travis speedup.

Merge C/C++ build steps on Travis

Conflicts:
	.travis.yml

Conflicts:
	.travis.yml

- Added ptag ignore annotation threshold
- prefixed everythig with grpc_
- removed spurious annotations in channel_create.c and client_channel.c
- removed stap_probes.h (it's generated from stap_probes.d by make)
- Updated Makefile and its template with the right way to generate stap
  probe headers from its .d definition.

Incoming stream id validation fixes

Ref the cached default creds so that we do not crash next time we use it....

Move end_threads to subclass 

Fix thread local storage error in iOS build

Unify transport & channel op interfaces

Capure thread id with default timer implementation