Add copyrights to docker files, makefiles

tools/distrib/check_copyright.py

tools/dockerfile/grpc_base/Dockerfile

tools/dockerfile/grpc_clang/Dockerfile

tools/dockerfile/grpc_cxx/Dockerfile

tools/dockerfile/grpc_go/Dockerfile

tools/dockerfile/grpc_java/Dockerfile

tools/dockerfile/grpc_java_base/Dockerfile

tools/dockerfile/grpc_node/Dockerfile

tools/dockerfile/grpc_node_base/Dockerfile

tools/dockerfile/grpc_php/Dockerfile

tools/dockerfile/grpc_php_base/Dockerfile

tools/dockerfile/grpc_python/Dockerfile

tools/dockerfile/grpc_python_base/Dockerfile

tools/dockerfile/grpc_ruby/Dockerfile

tools/dockerfile/grpc_ruby_base/Dockerfile

vsprojects/vs2013/Grpc.mak