implement undo and redo method for delete-name,-tag,-location,and -time
Merge branch 'master' of https://github.com/cs2103aug2014-t10-2j/main.git into UI
Added basic GUI and modified affected code
Created basic GUI. Cannot receive tasks from database.
updates:
- changed location character to '@'
- changed escape sequence to inverted commas
- allowed index range for delete in 2 formats (f1, f2 and f1-f5)
- allow flexible update by field - return commandAdd obj hasMissingArgs,
but with arguments intact, null/empty arraylist for unspecified fields
Merge branch 'UI'