Update performance.rst

Fix typos "tunning" -> "tuning".
Merge pull request #194 from ncjones/patch-1

Update performance.rst
Django 1.7 compatibility.
Moved test app for Django 1.7
Moved test app.
Moved test app.
application's name is required in the AppConfig.
Removed unused imports.
Pillow was missing.
create_permission API changed.
Django 1.7 + now requires setup to be called.
Added django 1.7 to tox.
Fixed rosetta problem at example project
Added Xavier to authors, updated changelog
Removed get_for_object methods from managers

This is related with #188
Updated tox/travis config to use Django 1.6.2
When not testing, guardian should not fail to import mock

related with #193
Merge branch 'devel' of github.com:kostko/django-guardian into kostko-devel
Added Jernej to AUTHORS file
Updated to Django 1.6.2 for mysql/postgresql tests