src/bugsnag: implement own polyfilling for requestAnimationFrame

Fixes #72 (`requestAnimationFrame` wrapper doesn't honor the passed
timestamp)

The old approach rely on `hijackTimeFunc`, which expects a callback to
accept at least two arguments. If the function being wrapped accepts
only argument, it is being swallowed.

Tested manually on IE 6,7,8,9,10, and modern Chrome.