add in test for conditional task
fix conditional date pair problem
tree map refactor
minor changes for tag storage
modify filter functions
Merge branch 'chuyu-storage' of github.com:cs2103aug2014-w13-4j/main into pn-logic-filter

Conflicts:
	src/models/Task.java
	src/tests/TaskStorageTest.java
Rename LogicAPI to Logic Api, step 1...(because Windows is case-insensitive)
Rename LogicAPI to Logic Api, step 2.
Show ID of dates in task display (need to think of a more elegant way of doing this)
Show "unconfirmed" if task is a conditional task and it is not confirmed.
Increase width to account for showing ID (need to check on systems with different display resolutions/DPI)
Removed redundant CommandParser initialization.
Merge branch 'master' of github.com:cs2103aug2014-w13-4j/main into pn-logic-filter
Add in filter for completed and active task. Command is filter status <completed/active>
Also added check that mandatory fields are present in adding/deleting tasks
Merge branch 'emmeryn-show-conditional-dates' of https://github.com/cs2103aug2014-w13-4j/main
resolve bug in dateparser
Merge remote-tracking branch 'origin/pn-logic-filter'
Merge branch 'master' of https://github.com/cs2103aug2014-w13-4j/main into emmeryn-basic-gui