Merge github.com:grpc/grpc into atm2

BUILD

Makefile

binding.gyp

build.yaml

config.m4

doc/connectivity-semantics-and-api.md

gRPC.podspec

grpc.gemspec

package.xml

src/core/ext/census/gen/README.md

src/core/ext/census/gen/census.pb.c

src/core/ext/census/gen/census.pb.h

.../ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h

src/core/ext/transport/cronet/transport/cronet_transport.c

src/core/lib/iomgr/ev_poll_and_epoll_posix.c

src/core/lib/iomgr/ev_poll_and_epoll_posix.h

src/core/lib/iomgr/ev_poll_posix.c

src/core/lib/iomgr/ev_posix.c

src/core/lib/iomgr/tcp_server_posix.c

src/core/lib/surface/call.c