Removed some unused files.

Added logic for calculating status.
Completed MainPage Status PivotItem.
Fixed bug where Dates were out of order after adding new date.

Fixed bug where removing today's entry did not re-add the Add Today AppBarIcon.
Fixed bug where adding today's entry did not remove the Add  Today AppBarIcon.
MainViewModel code cleanup.
Fixed small UI bug where changing PivotItem showed the DatePicker briefly.
Updated DatePicker styles.