Merge branch 'master' of github.com:google/grpc into httpcli_test

Makefile

build.json

examples/pubsub/pubsub.proto

include/grpc/grpc_security.h

src/compiler/python_plugin.cc

src/compiler/ruby_generator_map-inl.h

src/core/channel/channel_stack.h

src/core/debug/trace.c

src/core/debug/trace.h

src/core/httpcli/httpcli.c

src/core/iomgr/fd_posix.c

src/core/iomgr/fd_posix.h

src/core/iomgr/tcp_client_posix.c

src/core/iomgr/tcp_posix.c

src/core/iomgr/tcp_server_posix.c

src/core/security/google_root_certs.c

src/core/security/secure_endpoint.c

src/core/security/security_context.c

src/core/security/security_context.h

src/core/surface/call.c