update packaging to current upstream version

Hello,

I updated the package to the current django-extensions upstream version [1.2.0](https://github.com/django-extensions/django-extensions/releases/tag/1.2.0). I added the new [watch file](http://anonscm.debian.org/viewvc/sepwatch/trunk/watchfiles/python-django-extensions_0.6%2Bgit201107051902-1.watch?revision=13&view=co) linked from the [PTS page](http://packages.qa.debian.org/p/python-django-extensions.html) and refreshed the patch for the werkzeug installation advice. The new upstream version will fix the open RC bug [#690425](http://bugs.debian.org/690425).

Please apply the changes and upload a new version to the Debian archive. I would volunteer for co-maintenance of the package if you are interested.

Best regards
Jan Dittberner