[fix bug 907250] Add django-cache-machine to jinja templates.
* PEP8 beautifications.
[fix bug 912500] Don't delete mentees' userprofiles on mentor deletion.
[fix bug 912916] Don't delete related bugs on user's delete.
Merge pull request #485 from akatsoulas/907250

[fix bug 907250] Add django-cache-machine to jinja templates.
[fix bug 915133] Update django to 1.4.7 and playdoh.
Merge pull request #490 from akatsoulas/915133

[fix bug 915133] Update django to 1.4.7 and playdoh.