admin: use /usr/bin/env python for interpreter everywhere
admin: handle update to python 2.7

'with' keyword is now reserved and there was something up with
superclass constructors having changed
UrlSnarfer: update twitter helper to handle photo URLs
UrlSnarfer: add $ to denote spoilers in links
VishnuBrowser: add proxy support
UrlSnarfer: add ability to specify username in test mode