Datepicker: Clean up tests
Datepicker: Support changing the appendTo option after init

Adding tests for the appendTo option.
Datepicker: Various changes for the showWeek option.

* Re-add ui-datepicker-week-col class name currently used.
* Add test suite.
* Support changing option after initialization.
Datepicker: Support position option changes after init

Added position option tests.
Datepicker: Support changing eachDay after initialization

Add tests for eachDay.
Datepicker: Allow dateFormat to be changed after init

Add dateFormat tests.
Datepicker: Add test to ensure the <input>'s value is preselected
Datepicker: Support destroying inline datepickers.
Datepicker: Add value() and valueAsDate() methods
Datepicker: Fix key handling implementation and tests
Datepicker: Use Globalize 1.0.0
Datepicker: Update key handling implementation and tests
Datepicker: Re-adding mouse tests.
Datepicker: Adding an isValid() method.
Datepicker: Handle for invalid values in value() and valueAsDate()
Datepicker: Update the picker as the user types valid dates
Date: Updating test suite to coding standards.
Date: Make $.date() a constructor function. Move methods to prototype.
Datepicker: Fix code style issues
Datepicker: rename select method to _select

Make select() a private method as it's not part of the specification.