Timesheet view model is added. Other changes.
Merge branch 'master' of https://github.com/sherpadesk/Windows

Conflicts:
	SherpaDesk/Models/CalendarCell.cs
	SherpaDesk/Styles/CustomStyleSelector.cs
	SherpaDesk/Styles/TimesheetResources.xaml
	SherpaDesk/Timesheet.xaml
	SherpaDesk/Timesheet.xaml.cs