Django 1.7 support

[kaedroho]

All the bugs blocking the previous attempt to add Django 1.7 support seem to be fixed now.

Wagtail has moved on so much since then, so this pull request starts adding Django 1.7 support again from scratch.

• Create initial schema migrations
• Create initial data migrations
• Update ElasticSearchQuerySet to use Django 1.7 where nodes
• Get all tests working (one more test to go)
• Test

How you can help:

• Test Wagtail with Django 1.7 features and let us know if you have any problems
  • use pip install -e git://github.com/kaedroho/wagtail.git@56e4dac#egg=wagtail
  • or add -e git://github.com/kaedroho/wagtail.git@56e4dac#egg=wagtai to your requirements.txt
• FIXED Theres a couple of places where Wagtail loops over INSTALLED_APPS. This doesn't take into account INSTALLED_APPS can now contain Django 1.7s AppConfigs (https://docs.djangoproject.com/en/dev/ref/applications/#for-application-users). These need to be changed to take these into account.
  • https://github.com/torchbox/wagtail/blob/100797796df0bc8ca96035092f32a9275d2b3713/wagtail/wagtailcore/hooks.py#L43-L49
  • https://github.com/torchbox/wagtail/blob/100797796df0bc8ca96035092f32a9275d2b3713/wagtail/wagtailimages/formats.py#L88-L94
• FIXED There's a test that is failing on Python 3.4. It looks like a unicode/bytes issue: https://travis-ci.org/torchbox/wagtail/jobs/31053446#L308

[kaedroho]

One test is still failing but I don't think the particular test in question is any cause for alarm.

This is now ready for review.

[kaedroho]

Is there anything wrong with merging this soon? I think it would be really useful to have the community test this and help fix any bugs before it is released. AFAIK, there are no regressions (the only bugs I know of affect only Django 1.7 users of which there are currently none).

[kaedroho]

I've added a section to the top of this document showing the things that need to be done before Django 1.7 support is complete.

I wouldn't consider any of the above issues to be merge blockers (as they don't affect existing users) and would be perfectly acceptable to give Wagtail "Django 1.7 support is in alpha" status.

[sirex]

Just did some manual testing with Django 1.7c2 and found no issues, everything seems to be ok.

+1 To merge it to master.

My code with Django 1.7c2 is here:
https://github.com/python-dirbtuves/akl.lt/tree/wagtail-django-17

[kaedroho]

I've merged master into this branch and I've added instructions above for how to use this in your projects.

If anyone does use this, let us know how you get on and any bugs you come across.

[kaedroho]

I've overwritten the migrations as some minor tweaks have been made to Djangos migration format recently. This appears to fix the Python 3 issues. I don't expect to have to do this again though.

[gasman]

Unfortunately this is failing on sqlite (the 'py27-dj17-sqlite' environment in tox) with "KeyError: u'page_ptr'" during migrations.

[kaedroho]

Just remade the migrations for the tests app which seems to fix the issue