[WIP] Update web/compatibility.js

1) Remove obsolete workarounds
2) Add support comments

Original description:
`Object.create` & `Object.defineProperty` issues concern IE<9 and really old WebKit versions. `Object.keys` is universally available outside of oldIE as well, including Android 2.3. Firefox has unprefixed `requestAnimationFrame` long ago and the fallback to using a custom function is only slower but works.