Replace old Easer module with a tween.js port
namespace Transition in Moon
Added easing_spec
Easing, missing Math.pow method fix

Math.pow from JS is the same as ruby's ** method
Interpolation Math.pow and Math.floor fixes
Code Gardening, removing excess spaces from brackets
Added interpolation_spec
Interpolation bug fixes
namespaced Transitionable and TransitionHost under Moon
Transition now accepts easer as the last parameter
Fixed Transition easing going out of control with non Linear Easing
RenderContainer#render_elements now takes optional options parameter