Safari Pixel Rounding Fix

Safari automatically anti-aliases when not drawing to the canvas with pixel-perfect (integer) coordinates. I imagine this should be fixed by setting the CanvasRenderer.renderSession.roundPixels = true, but this can result in weird behavior if a Sprite frame offset is not an integer (eg. x-anchor at .5 on a 15-pixel wide sprite results in a dx of -7.5).

This might not be the best way to fix this, but I'm just truncating the decimal from the dx and dy frame offsets. It seems to work for me.

Before: http://jsfiddle.net/jiminychris/z3srL5dy/

After: http://jsfiddle.net/jiminychris/mygLLr9c/

Note that these should look exactly the same in Chrome, and this was only an issue in Safari, as far as I can tell.