[Parser] various option fixes & implementation

1. Tidied up the unit test for better categorization and coverage
2. Implemented remove tag, solved repeat and recursive logic by making
sure that only delete and complete can use it.
3. Now supports very short time format like 4pm and dot format like
4.00pm
4. Complete task implemented

Next push:  certain amount of exception handling (return valid as false
and start implementation of fail field) Will talk to you guys soon