Get rid of denorm (unless it gets actually released)

[mjtamlyn]

cc @jturnbull

Denorm has no release on pypi so we can't really be using it. Either we should get rid of it (preferably by getting rid of the nested-ness of the categories by default) or by adapting the code so that it doesn't use denorm any more. Perhaps look at how FeinCMS does its _cached_url property

[jturnbull]

I'd propose two different category extensions: this, the hierarchical category setup (we should stick the latest denorm on pypi) and a new, simple flat category extension.

[mjtamlyn]

+7000000

[meshy]

We could bundle denorm in the same way the packages are bundled in requests...

[meshy]

If i'm not mistaken, denorm will fail when it comes to django 1.6's new way of doing transactions. Perhaps we should get rid of it even if it ever does get on pypi.

[mjtamlyn]

That depends which version of denorm you're using, but yes there is an issue there.