Django-tables2

- Fix bug that caused an ordered column's `<th>` to have no HTML attributes.

- Updated example project to add `colspan` on footer cell so table border renders correctly in Webkit.
- Fix regression that caused 'sortable' class on <th>.
- `Table.__init__` no longer *always* calls `.order_by()` on QuerySets, fixes 55.
This does introduce a slight backwards incompatibility. `Table.order_by` now has the possibility of returning `None`, previously it would *always* return an `OrderByTuple`.
- `DeclarativeColumnsMetaclass.__new__` now uses `super()``
- Testing now requires pylint and Attest >=0.5.3

- Fix regression that caused column verbose_name values that were marked as
safe to be escaped. Now any verbose_name values that are instances of
SafeData are used unmodified.

- Fix regression in `SingleTableMixin`.
- Remove stray `print` statement.

- `SingleTableView` now uses `RequestConfig`. This fixes issues with
`order_by_field`, `page_field`, and `per_page_field` not being honored.
- Add `Table.Meta.per_page` and change `Table.paginate` to use it as default.
- Add `title` template filter. It differs from Django's built-in `title` filter
because it operates on an individual word basis and leaves words containing
capitals untouched. **Warning**: use `{% load ... from ... %}` to avoid
inadvertently replacing Django's built-in `title` template filter.
- `BoundColumn.verbose_name` no longer does `capfirst`, capitalizing is now the
responsibility of `Column.header`.
- `BoundColumn.__unicode__` now uses `BoundColumn.header` rather than
`BoundColumn.verbose_name`.

- Fix version in `setup.py`