Added cusomized display feature to Controller and Data

Implemented customized display to support the customized display of
tasks of a certain taskType, within a certain time period or with a
certain status using the following command structure:
display [DateTimePeriod] [type] [status]

Remarks:
[..]: optional parameter; squence of paramter doesn't matter
DateTimePeriod: e.g. oct 3 to oct 10 3pm; if the start time is left out,
the program automatically assumes the current DateTime as startDate
type: none (floatingTasks), deadline (deadlineTasks), timed (timedTasks)
status: done, undone

Examples:
display oct 10 3pm
--> displays all Deadline and Floating Tasks from today to Oct10 15:00.
display oct 3 to oct 10 3pm
--> displays all Deadline and Floating Tasks from Oct 3 00:00 to Oct10
15:00.
display none
--> displays all Floating Tasks
display deadline timed
--> displays all Deadline and Timed Tasks
display done
--> displays all Tasks marked as done
display undone oct 3 deadline
--> displays all undone Deadline tasks by Oct 3 00:00
Merge branch 'master' of
https://github.com/cs2103aug2014-f11-1j/TaskCommander.git

Conflicts:
	tasks.json