Added the followings:

1. DescriptionParser
2. DateParser
3. DateStringMassager
4. CommandParser
5. PriorityParser
6. ParserFlag
Added Test Case for ParserFlag
Incorporate parser flags to determine which parser succeed in parse manager
Comments for ParserManager
Add toString methods for all type of tasks
Add equals method for all type of tasks
Added initial test case
Improved date parser to handle date connector word ("at", "by", "from", etc)
Added more test cases for the new parser manager
Fix redo, undo, delete, edit command
Major changes to parser
Change string handler contains to containsword
Edited regex pattern for comparing date digit by next word, restrict it to catch delimited digit which was preceded by space
Merge branch 'master' of https://github.com/cs2103aug2014-t17-2J/main into Parser

Conflicts:
	WeDo/src/dataStorage/BasicDataHandler.java
Fix some conflict error
Modified the task parameter to return default value if it is null
Modified Task constructor with no parameter that help set default values