the name is the key of each task. edit the deleting.
changed method name

-changed from isDeadlineOrTimedTask to isTimedTask
modified add

-allowed adding of clashing tasks, but returns a clashing message
edited constant for clashing timeslots

- edited message for clashing timeslots
Merge remote-tracking branch 'origin/logic'
Merge branch 'master' of https://github.com/cs2103aug2014-t16-1j/main