[#99] added a polyfill for `performance.now`

this is way more simple than the previous code with the `highRestTimer`
support flag
[#99] object update function now provide the time elapsed since the last update

Except for the `me.game.update()`, since it's the main entry point for
the RAF callback, and `me.Timer.update()` since the delta is calculated
there first.
Merge branch '1.0.0-dev' into ticket-103-clean