Disable submit buttons upon form submission instead of click

`DEBUG_TOOLBAR_PATCH_SETTINGS` is obsolete in django-debug-toolbar 1.6. We also don't need to specify `DEBUG_TOOLBAR_PANELS` as it is identical to the default.

Enable the TinyMCE 'lists' plugin as this functionality was dropped from the core

The tests were failing on python 2 due to the fact that the __init__.py
wasn't written so it wasn't a valid module. With this commit we now
also fully leverage pytest functionality to handle temporary paths for
us.

See https://github.com/django-oscar/django-oscar/wiki/Releasing#contributors

Fix facet form scripting

Fix various deprecation warnings

Instead use `for line in fh` since that is less memory intensive

This fixes a DeprecationWarning

Since 1.10 these are properties on the user instead of
methods. The functions are for compat between 1.8+ and 1.10+

Latter one is deprecated

A dict_values object was returned instead of a list. See #2223

You cannot access object attributes directly from inside a blocktrans tag.

Results in too much clutter in Sentry