Add ThriftpyConnection module.

This module depends on thriftpy, which is a pure python implementation
for Thrift. It supports:

1. Python2.7+, including Python3.3 and Python3.4
2. pypy and pypy3
this would be used during sniffing to inspect the cluster to see what IP/ports the nodes are listening to. It must match the information in node info provided by the thrift plugin (`'thrift'`)