The new Uize.Widget.Picker.Date class implements a date picker widget, using a deferred loaded date picker modal dialog to let the user select a date.

The date picker widget supports the following key features...

	It lets you constrain the date range within which a user can select a date by specifying values for the minValue and maxValue state properties.
	The way that the currently selected date is displayed in an instance's input implied node can be configured using the displayFormat state property.
	The dialog that is launched to let the user select a date is deferred loaded, so that it does not add to the initial load time of the page.
	Multiple instances of the Uize.Widget.Picker.Date class share the same date picker dialog instance.
	When the date picker dialog is launched for a specific Uize.Widget.Picker.Date instance, the dialog is "moored" to the root node of the instance's selector button.
	You can specify a custom date picker dialog class that should be used for selecting a date.