sprites can now use images and canvases (in addition to image file paths) as the source for the base image
added support for scaling world resolution
improved the way Actor physics is calculated (now more accurate, supports slipperiness)
standardized tense of method description verbs
added favicon
added some minor changes to better support mobile devices
upgraded to jQuery 1.9
renamed utilities.js to boilerplate.js
hid some private variables in closures