Fixed clang-format sanity error

Add interop test for Cacheable Unary Calls

Upmerge doc changes from v1.0.x

Several improvements to README.md files

Fix building ruby artifact

Fixed local cloning of grpc/grpc submodules on docker

Safe server shutdown.

Check for the correct number of orphan callbacks in udp_server_test

Adding a method in channel creds to remove any attached call creds.

v1.0.x → master upmerge.

change back slashes to forward slashes in grpc.tool nuspec

Change C++ API to expose wait_for_ready instead of fail_fast.

PHP: require grpc extension to be installed before composer package