adding dummy
selection manager part 2
Fixing some event routing bug in jbox2d, and added mouseClick event.
So, when we are only interested in mouse click or double click,
we will not have to worry about mouse click up or down.

Previously, due to the bug of this framework,
each teset would get 4 mouseup event!
The world got flipped by the commit 5fbef851d610638edd77343cdc6c323b79f846c9
So, I am fixing this one.
Merge pull request #9 from karpark/fixForFlippedWorld

Mouse Event plumbing : Enabling mouseClick