More integration docs updates

Added note about South 1.0 and Python 3.x bug with workaround
Added note that Django 1.5.x is no longer a supported release
Moved ``pip install django-cms`` until *after* the virtualenv has been created
Changed docs to use ``sudo`` when installing virtualenv based on feedback from @yakky
Fixed a reference to html5lib beta release since pip will not install automatically
Added back uploaded media handling to example url patterns (static handled automatically by runserver)
Added back ``admin.autodiscover()`` for Django <=1.6