Django-tables2

- Added Hungarian translation [471](https://github.com/bradleyayers/django-tables2/pull/471) by [hmikihth](https://github.com/hmikihth).
- Added TemplateColumn.value() and enhanced export docs (fixes [470](https://github.com/bradleyayers/django-tables2/issues/470))
- Fixed display of pinned rows if table has no data. [477](https://github.com/bradleyayers/django-tables2/pull/477) by [khirstinova](https://github.com/khirstinova)

- Added `ManyToManyColumn` automatically added for `ManyToManyField`s.

- Allow customizing the value used in `Table.as_values()` (when using a `render_<name>` method) using a `value_<name>` method. (fixes [458](https://github.com/bradleyayers/django-tables2/issues/458))
- Allow excluding columns from the `Table.as_values()` output. (fixes [459](https://github.com/bradleyayers/django-tables2/issues/459))
- Fixed unicode handling for column headers in `Table.as_values()`

- Allow computable attrs for `<td>`-tags from `Table.attrs` ([457](https://github.com/bradleyayers/django-tables2/pull/457), fixes [#451](https://github.com/bradleyayers/django-tables2/issues/451))

- Feature: Added an `ExportMixin` to export table data in various export formats (CSV, XLS, etc.) using [tablib](http://docs.python-tablib.org/en/latest/).
- Defer expanding `Meta.sequence` to `Table.__init__`, to make sequence work in combination with `extra_columns` (fixes [450](https://github.com/bradleyayers/django-tables2/issues/450))
- Fixed a crash when `MultiTableMixin.get_tables()` returned an empty array ([454](https://github.com/bradleyayers/django-tables2/pull/455) by [pypetey](https://github.com/pypetey)

- Call before_render when rendering with the render_table template tag (fixes [447](https://github.com/bradleyayers/django-tables2/issues/447))