Merge github.com:grpc/grpc into qps_driver

.travis.yml

Makefile

build.json

src/compiler/python_generator.cc

src/core/channel/channel_stack.c

src/core/channel/channel_stack.h

src/core/channel/connected_channel.c

src/core/debug/trace.c

src/core/debug/trace.h

src/core/iomgr/iomgr_posix.c

src/core/iomgr/tcp_posix.c

src/core/iomgr/tcp_posix.h

src/core/security/secure_endpoint.c

src/core/security/secure_endpoint.h

src/core/surface/completion_queue.c

src/core/surface/init.c

src/core/surface/init.h

src/core/surface/init_secure.c

src/core/surface/init_unsecure.c

src/core/surface/surface_trace.c