(WIP) Add a subclass of SessionMiddle (django.contrib.sessions) which is Micro...

...site aware and allows for the cookie domain to be overriden to give better session partitioning of a user
@ormsbee maybe there's a slightly more "pythonic" approach to this? I recall seeing some @wrap() decorators around in the code, but I'm not sure if it is applicable here? In any case probably wouldn't clean it up too much.