refactor isElemInViewport to use vF in both directions
refactor:(element style and config factories), fix:(flickering bug fixes #65 #70)
fix:(opacity delay properly zeroed for reset transitions)
Refactor configFactory() and add 'hustle' easing
Refactor style factory. Add support for scale transformations.
WIP for 0.2.0
WIP refactor styleFactory with build method
Delay control added to config object and animate()
Code cleanup.