add destroy method to widget api (button not erased)
Add _getDateMonthpicker method

Allow retreival of the currently selected date via a call to:
`instance.monthpicker("getDate")`
Add QUnit testing library files
Modernizing the Monthpicker widget

Add structure and mouse unit tests from the jQuery UI Datepicker widget.

- Add getDate method to check widget's current state.
- Remove usage of onclick attributes.
- Add button panel with 'Current' and 'Done' buttons.
- Add the bulk of the core set of unit tests.

Fixes #1.
Update demo index.html

Use recent version of jQuery and jQuery UI. Display the button panel on
monthpicker two (with different settings).