Fix Absence related bugs

Absence Status - when a request has been approved it shows a status of
Completed which should be changed to Approved.

Absence Requests - after an Absence request has been created and saved, the user should automatically return to the My Absences page.

Statistics View - in this view the Toil Credit balance shows as a negative
number, while it shows as a positive number in the List View. IToil Credits to show as positive numbers in both views.