This commits prevents Util from modifying the window object.
- `window.requestAnimFrame` was removed (no polyfill is needed anymore)
- the potential redefinition of `console.log` and friends was removed
(all supported browsers have `console.xyz` defined anyway)
This commit restructures noVNC, splitting it into the core directory
and the app directory, with the former containing core noVNC parts,
and the latter containing parts specific to the application.