build_list_filter method added to ModelListView. This method take care of ModelAdmin2.Meta.list_filter option
Added djadmin2.filters module.

This module is handling list filter creation by inspecting the model of
supplied queryset. Contains default mapping for field type filters to
our custom form widgets that are rendering links instead of inputs.
Added list_filter block
Added list_filter attribute to contrib's admin, admin2 definition of Post, Comment model admin.
Merge remote-tracking branch 'upstream/develop' into list_filter

Conflicts:
	djadmin2/views.py
add docs to our custom widgets and default mapping, just to not formatting
Added id to list_filters container
Removed unused imports
Added simple test for presence of list_filter container
minor bugfix
Added basic test for list_filter feature
Added django-filters to requirements
Merge branch 'list_filter' of git://github.com/beezz/django-admin2 into beezz-list_filter