Add support for F5 Big/IP devices

Both SSH (CLI) and iControl API should be supported.

iControl References
===================

Python iControl library
https://devcentral.f5.com/community/group/asg/4

Code samples (requires login):
https://devcentral.f5.com/wiki/icontrol.pycontrol_v2.ashx

iControl white paper:
http://www.f5.com/pdf/white-papers/icontrol-wp.pdf