Admin, Calendars; updated User Interface functionality

The following enhancements have been made to the Admin, Calendars form.

• Non-Working Days
• Can now be edited directly on the grid
• New button to sort dates into order (note a date can only be defined once so this removes duplicates)
• Add drilldown now allows a range of dates to be added
• Add Holidays
• "Clear existing Holidays?" default is now unchecked
• From date now defaults to the start of month (previously this was the start of the year)