WIP: Animation Service

This is a work in progress branch for the revamped Javascript animation service for Ionic.

- [x] Inspect Facebook Pop and iOS APIs
- [x] Design API
- [x] Enable slow animation handling (for debugging)?
- [x] callbacks/tracer for analyzing an animation later (for debugging)?
- [x] Think about hooking into wip-physics or just approx
- [x] Support delaying animation
- [x] Support reversing animation
- [x] Support repeating animation
- [x] Support auto reversing
- [x] Pause and restart
- [x] Step through
- [x] Spring dynamics
- [ ] Damping
- [x] Gravity

More to come soon.

Mental note: tons of easing functions here: http://gsgd.co.uk/sandbox/jquery/easing/jquery.easing.1.3.js
Default CSS timing functions from blink source: https://github.com/yoavweiss/Blink/blob/34a398f1ea7709604aabd69fc341cc2a2ee8ac18/Source/platform/animation/TimingFunction.h