Docs: minor fixes
Docs: Add external links to Pootle docs conf
Use docs.translatehouse.org not readthedocs.org URLs
Fix docs domain
Copyright header corrections.
Import from django.conf.urls.

django.conf.urls.defaults is deprecated since Django 1.4 and will be
removed in Django 1.6.
Removed dead code.
Add SuperuserRequiredMixin.

Useful for Class-Based Views.
Updated hacking instructions.
Update docs/ theme
Removed dead declarations.
Simplified selectors.
Make input button styling available for btn classes too.
Adapted UI elements in preparation for more page types.

Class-based generic views have been used for this, since functionality
will be mostly shared by other types of pages. Small bits might still be
missing, but will be reviewed as part of bug 2866.

Fixes bug 2865.
Fixed template path.
Moved intra-field validation to models.
Set explicit field ordering.
Implemented generic page display.
Rather extend the base template.
Use a more meaningful id.