[1.5.x] Fixed the reusable apps docs to use a rst file extension for the README and follow PEP8 a bit more.
[1.5.x] Fixed the reusable apps docs to use a rst file extension for the README and follow PEP8 a bit more.

Backport of 949b4e94588e73067f64b5b6d22e569a105baaf7 from master.

ccn-2m/django,hasadna/django,imtapps/django-imt-fork,bliti/django-nonrel-1.5,alx-eu/django,ccn-2m/django,ccn-2m/django,ccn-2m/django,bliti/django-nonrel-1.5,hasadna/django,alx-eu/django,alx-eu/django,bliti/django-nonrel-1.5,hasadna/django,alx-eu/django,imtapps/django-imt-fork,imtapps/django-imt-fork