Merge branch 'delayed-write' into grand-unified-closures

.travis.yml

examples/objective-c/auth_sample/AuthTestService.podspec

examples/objective-c/auth_sample/Podfile

examples/objective-c/helloworld/HelloWorld.podspec

examples/objective-c/helloworld/Podfile

examples/objective-c/route_guide/Podfile

examples/objective-c/route_guide/RouteGuide.podspec

gRPC.podspec

include/grpc++/support/slice.h

src/compiler/config.h

src/compiler/cpp_generator.cc

src/compiler/cpp_plugin.cc

src/compiler/csharp_generator.cc

src/compiler/csharp_generator_helpers.h

src/compiler/csharp_plugin.cc

src/compiler/generator_helpers.h

src/compiler/node_generator.cc

src/compiler/node_generator_helpers.h

src/compiler/objective_c_generator.cc

src/compiler/objective_c_generator_helpers.h