THRIFT-922. cpp: Update C++ generator to emit templatized code

THRIFT-922. cpp: Update C++ generator to emit templatized code

When the "templates" option is passed to the C++ generator, it now emits
templatized versions of the client and processor.  Generated types emit
templatized read() and write() functions.

This allows the generated code to invoke the correct non-virtual
TTransport and TProtocol implementations, resulting in faster
serialization and deserialization.

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@1005138 13f79535-47bb-0310-9956-ffa450edef68