Datepicker: Fix old MediaWiki links.  Fixes #104.
Widget: Document how to retrieve a widget's instance and how to tell whether an element has a widget bound to it.  Fixes #77.
Spacing consistency.
Spell checking o_O
Widget: Give example of getting all elements that are instances of the widget.
Updating link to the :data selector.
Merge branch 'widget_instance_docs'