Merge remote-tracking branch 'upstream/v1.1.x' into node_disable_libuv_core

gRPC-Core.podspec

gRPC-ProtoRPC.podspec

gRPC-RxLibrary.podspec

gRPC.podspec

src/objective-c/!ProtoCompiler-gRPCPlugin.podspec

src/objective-c/GRPCClient/private/GRPCHost.m

src/objective-c/GRPCClient/private/version.h

templates/gRPC-Core.podspec.template

templates/gRPC-ProtoRPC.podspec.template

templates/gRPC-RxLibrary.podspec.template

templates/gRPC.podspec.template

...rc/objective-c/!ProtoCompiler-gRPCPlugin.podspec.template

...tes/src/objective-c/GRPCClient/private/version.h.template