Calendar: Add calendar widget

Add calendar widget by copying and renaming datepicker widget files
Calendar: Add missing AMD dependency todo comment
Calendar: remove datepicker functionality, options and methods
Calendar: Fix focus highlighting when month is changed
Calendar: Make use of uniqueId method
Calendar: Add _isValid method

Add a basic _isValid method for both widgets to check for valid dates.
Datepicker: $.date.selected() should return the actual date object

The method should return the actual date object instead of the copied $.date
object
Datepicker: Remove calendar functionality, options and methods
Calendar: Add min and max option

Add min and max option by extending _isValid method and improving render day
cell mechanism
Datepicker: Add min and max option
Datepicker: Remove select callback reference
Calendar: Remove select callback reference
Calendar: Fix min / max option incl. refresh after setting option
Datepicker: Fix date range demo
Datepicker: Remove unneeded inline demo file
Datepicker: Read and write min / max attributes
Datepicker tests: Add Calendar widget dependency to unit tests
Datepicker tests: Remove inline Datepicker unit tests
Datepicker: Simplify calendar generation

Simplify calendar generation, use CSS instead of inline styles, fix
destroy method
Calendar: Simplify calendar generation

Simplify calendar generation, remove unneeded inline styles