Fix support for postimg.org
Example:
http://postimg.org/image/mvr0zv2fn/
-> http://postimg.org/image/mvr0zv2fn/full/
-> http://s13.postimg.org/dnysj5vdh/screen1.jpg
Don't save intermediate redirects in history with allowBack = false
Bump version to 0.5.23 - 2014-09-16