Added conditional param to ADD
Reformatted task model, and added conditional method in task modifier
Merge branch 'command-conditional' of github.com:cs2103aug2014-w13-4j/main into pn-logic
Support display of individual task
Remove interface
Remove override
Changed parameters of add, delete to take in param instead of the entire command
Merge branch 'pn-logic-display-task' of github.com:cs2103aug2014-w13-4j/main into pn-logic

Conflicts:
	src/logic/Logic.java
	src/tests/LogicTest.java
Implemente conditional command
Remove debug message
Update now support the same functions as add, except conditional params
Merge branch 'command-conditional' of github.com:cs2103aug2014-w13-4j/main into pn-logic
Implemented conditional dates
Updated test