Added the ability to set an initial STUN Server host port.
Update __init__.py

Updated to match changes made in the next commit.
Update cli.py

Updated to give better help from the terminal on how to specify the host STUN server port.
Update README.rst

Updated to include the -P parameter for defining the initial port to connect to the host STUN server on.
Update README.rst

Clarified usage for -P.
Merge pull request #5 from keyneom/develop

Added the ability to set an initial STUN Server host port.