Django 1.4 Support.

This code appears to work fine with Django 1.4 (with the exception of the force_str stuff).

I'm not exactly what force_str will do differently, especially in the context of the two places it was used.

One of these was just a string to begin with, the other is an interpolated string.


One change allows easy swapping out of the RedisContext object, which will be useful to allow different 'channels' or whatever.

The other fix is pretty minor (use SERVER_NAME instead of localhost).