Bandit 0.12.0

New since last version:
 - Fixed multiline string line number reporting
 - Stevedore based extension system
 - New paramiko shell injection test
 - Misc bug fixes
 - Updated README file
 - Added verbose output flag
 - Added Python 3.4 compatibility
 - Reported version of Python Bandit is using
 - Added documentation for some plugins
 - Added XML output support