When RDC are only used as the libraries, the user can choose not to build
the rdci and rdcd, which will remove the dependencies to the gRPC and protoc.
The -DBUILD_STANDALONE=off should be pass to the cmake.
* Change README.md for the instructions.
* Move the python_binding installation from client/CMakeLists.txt to CMakeLists.txt
so that the RDC library only build will also install the folder.
* Change CMakeLists.txt and rdc_libs/CMakeLists.txt to build with gRPC only if
the BUILD_STANDALONE is enabled.
Change-Id: If9cfe9fc298a83636d85fe352a311fe2fe041661
Bill(Shuzhou) Liu
105675aeeb