Merge github.com:grpc/grpc into seqno2

.travis.yml

gRPC.podspec

src/core/channel/call_op_string.c

src/core/iomgr/tcp_posix.c

src/core/surface/call.c

src/core/surface/init.c

src/core/transport/chttp2_transport.c

src/core/transport/chttp2_transport.h

test/cpp/qps/client_async.cc

tools/gce_setup/cloud_prod_runner.sh