Added Search within date period

add search within date period with accompanying test
update_logic
Merge branch 'master' of https://github.com/cs2103aug2014-w11-4j/main into update_logic

Conflicts:
	src/Logic.java
delete_Task tests added
delete_Update tests added
Complete parsing for all commands

Now parser can parse all commands but not at the optimum flexibility
and natural language acceptance.
Merge branch 'master' into interface
Updated dateRegex for proper date/time extraction
Initial integration between interface and logic
Merge branch 'interface'
Merge branch 'update_logic'

Conflicts:
	src/Command.java
	src/Logic.java
	src/MenuInterface.java
	src/Parser.java
	test/LogicTest.java
Add database.xml to .gitignore
Remove database.xml