Revert "Added pixi.js to the gruntfile."

This reverts commit ace3051099b0f09c659964bbf103998c29fa9b50.
Revert "Added pixi.js. Pixi is going to be our 2D webGL renderer with canvas fallback!"

This reverts commit feea31631c047a264ff017a49f043040dd5db33e.
Revert "Render object now uses Pixi and has a render loop."

This reverts commit 3f146db632dafcebb7512548c4c3e924d4fad9c9.
Revert "Initialize no longer initializes the canvas, this is a responsibility of the render object."

This reverts commit 28baea19e350490786dcd692c66fe68486d00688.
More rollback, decided to drop Pixi.js. I don't want to reinvent the wheel, i want to create a game.