Django-jchart

* Better Django backwards compatibility
* Improved sizing of the chart container html element

* Added custom chart configuration options through the use of the `options` class field

* `get_datasets` method is type checked. When an instance of the `Chart` class returns somtehing different than a list this results in a ValueError

* Added support for several bar chart specific Axes config properties (e.g. barPercentage)

* Added support for non async chart parameterization with `render_chart` template tag