Fixed bug in UndoCommand.
Passes test case for undoadd
Added test cases for delete and update.
Commented out all code related to ByteArrayOutputStream to enable usage of console for debugging. Feel free to uncomment it
Merge branch 'master' of https://github.com/cs2103aug2014-w09-1j/main

Conflicts:
	src/mytasks/logic/LogicTest.java