Make set_seed a well_behaved decorator

[jsatt]

The set_seed decorator was returning a function with a name of "_wrapper" instead of the name of the function it was decorating. This caused tests to not be run under the Django Nose test runner since nose requires test names to contain "test".

[coagulant]

I like the idea of fixing Nose runner. Due to our coding style differences it might take some time to manually merge the changes. Imho UUID support shouldn't be included, because it's custom field and obviously we can't support every non-standard field. Might be in contrib, however. Thnx for you pull request, though.

[travisbot]

This pull request fails (merged 8cd41cb8 into 30d966af).