django 1.6 password reset compatibility fixes

This pull request fixes password reset on `django>=1.6.0`.

It adds password reset wies tests and creates new submodule named `userena.compat`. This is proposition to handle in future any compatibility issues.

**Note** that this pull request depend on #386. Merge #386 before merging this one or simply forgot about #386. Sorry for that inconvienience but I was in hurry and wanted to contribute my code ASAP because I need that fixes in my production application. I simply simply don't want to watch if earlier PR was accepted and merged, because I could forget to create new one.

Finally I couldn't be sure that my fixes doesn't break anything without merging #386.

This pull request fixes/closes issues #381, #384, #372, #371 without duplicating urls in `userena.urls` or changing url names.