Add Waffle.io Badge

fixes #27
Add note about the Waffle.io badge
Merge pull request #30 from RobLoach/27-badge-waffleio

Add Waffle.io Badge
Add waffle.io badge to HISTORY.md

This does not make a new release. Just a note about it for any upcoming one.
v0.3.10. Improvement.

- v0.3.10 February 6, 2014
	- Added [Waffle.io](http://waffle.io) badge
	- Added Wishlist badge