Merge github.com:grpc/grpc into credit

include/grpc++/async_unary_call.h

include/grpc++/channel_interface.h

include/grpc++/client_context.h

include/grpc++/completion_queue.h

include/grpc++/config.h

include/grpc++/impl/call.h

include/grpc++/impl/client_unary_call.h

include/grpc++/impl/rpc_method.h

include/grpc++/impl/rpc_service_method.h

include/grpc++/impl/service_type.h

include/grpc++/server.h

include/grpc++/stream.h

src/core/surface/call.c

src/cpp/client/client_unary_call.cc

src/cpp/common/call.cc

src/cpp/proto/proto_utils.cc

src/cpp/proto/proto_utils.h

src/cpp/server/async_server_context.cc

src/cpp/server/server.cc

test/cpp/qps/server_async.cc