setup.py: enforce django-polymorphic-tree 0.8.9 for Django 1.5 compatibility.
Provide hooks for structured admin monkey patching.

Projects can insert additional logic in the admin classes,
using the settings `FLUENT_PAGES_PARENT_ADMIN_MIXIN` and
`FLUENT_PAGES_CHILD_ADMIN_MIXIN`.

Template names are all implicitly loaded now,
so other classes can override the `change_form_template`.
The template can use `{% extends default_change_form_template %}` to
access the default logic.

Todo: documentation
Fix Python 2.6 compatibility
Add `FLUENT_PAGES_DEFAULT_IN_NAVIGATION` setting

Allows larger sites to set the default "Show in navigation" choice.
Remove old TODO item
Basic translation table in place. Saving works again in the admin
Fix errors so app pages work in the admin.
Split migrations for translated fields, so datamigration works properly.
Fix verbose_name title in the admin
Clear app reverse cache on migrations, avoid errors with deployment
WIP: multilingual URL resolving
Implement fallback/auto_create switches for TranslatedAttribute

Also make sure the initial migration uses the fallback language,
so all migrated content will be visible regardless of the
frontend/backend language. (typically the same, but sometimes the
frontend language differs).
Fix translation missing-error for .only() objects.
Move translated_kwargs check to base TranslatableModel class.
Fix LANGUAGE_NOT_FOUND marker issues with pickle, use None instead.
Filter by language in page dispatcher, allow fallback language.
Fix unique constraint at translation table, fix south migrations
Smallfix in dispatcher: Add attempted languages in 404 message
Clarify form code bits
Admin: pass ?language= to URL, existing objects can be translated now.