Merge github.com:google/grpc into qps_driver

Makefile

README.md

build.json

include/grpc++/credentials.h

include/grpc/grpc_security.h

include/grpc/support/atm.h

include/grpc/support/sync.h

include/grpc/support/sync_posix.h

include/grpc/support/sync_win32.h

include/grpc/support/time.h

src/compiler/cpp_generator.cc

src/core/httpcli/httpcli.c

src/core/json/json.c

src/core/json/json_reader.c

src/core/json/json_writer.c

src/core/security/auth.c

src/core/security/credentials.c

src/core/security/credentials.h

src/core/security/credentials_posix.c

src/core/security/credentials_win32.c