Change Log 2013-12-23-A

Code updates/refactoring
1:  Removed unused code
2:  Added _get_blocked_date function to load blocked dates from database
3: Added code to check that blocked date does not already exist
4: Schema modifications:
4a: Dropped non-unique index on zen_vupoint_blocked_dates(blocke_date
column)
4b: Created unique index on zen_vupoint_blocked_dates(blocked_date)