Add a mostly cythonized version of the framed transport.

Use the TCyBufferedTransport to wrap the framed transport. This gets most of the performance since there's ~ 1 call to read/write to the framed transport anyway.
Also simplify TFramedTransport - don't buffer writes; just wrap the transport in a buffered transport.
Also don't rewrite sendall.
Merge pull request #66 from mikekap/develop

Add a mostly cythonized version of the framed transport.