refactor `self.models.objects` into a method

This allows easy overriding of the objects returned to the admin.
Add full support for SQ.Enum field
Added the tests directory to MANIFEST.in
Merge pull request #189 from ArtemSerga/_choices

Add full support for SQLAlchemy.Enum field
Fixed #183. Properly handle callable defaults
Split HTML functional pieces into separate libraries
Updated examples, added wysiwyg example
Merge pull request #193 from sYnfo/master

Tests failing in source distribution -- MANIFEST.in fix
Layout sample wip
SQLAlchemy 0.8 support
Layout sample and some template modifications
Some more changes
Merge pull request #195 from matchbox/get_queryset_method

refactor `self.models.objects` into a method
get_query() for ORM backends
Documentation update
Use Flask-BabelEx extension
Updated readme
1.0.5 changelog
Draw filters in a table
Wording in readme