Ensured that socket timeouts are only set for ephemeral sockets.

Added ability to use an existing socket to send requests from.

get_ip_info now accepts a 'sock' argument that, if passed,
forces the use of that socket for sending requests, and stops
PyNAT from closing it when done.

Fixed SO_REUSEADDR error. Added displaying of internal IP.

Added project url to setup.py

Added information to README.rst.

Refactored project.