Fix missing bits of test

Travis will now grab the newest point releases of Django, including 1.6.5

Also added 'bootstrapform' to test settings to reduce failing tests to actual bugs
Remove --use-mirrors
Grab requirements.txt for tests and remove Django 1.3 testing (requirements.txt asks for Django>1.4)
Give CustomField.empty_selection_list a default value

BooleanField defaults to False <1.6 and to None >=1.6, causing tests to fail on 1.6
Move CustomField to field class code to a mixin
Merge pull request #215 from Inboxen/form-mixin

Move CustomField to field class code to a mixin
Merge pull request #214 from Inboxen/testing-fixes

Testing fixes
Add `submitter` to Ticket model
Tabs to spaces
Remove debug template, django-debug-toolbar is better at that job
Remove API, we won't be using it
Use standard login/logout views