Potential performance improvements

- Remove argument validations from viewport methods
- Use requestAnimationFrame to separate the creation/appending of the
render element, from the start of the animation.  Possibly addresses
issue #22
- Add requestAnimationFrame non-invasive polyfill (doesn't overwrite
window.requestAnimationFrame) for internal use (taken from Velocity)
Updating dist files for publish Thu Nov  6 17:15:30 MST 2014
0.0.1-33