Simplify the Tween object

[thednp]

There's alot of stuff stored in the Tween function's this that are actually not needed in the scope of execution, and they take a huge chunk of memory. However, we do want to pass it to all string parsing functions.

UPDATE:

• now the Tween constructor is getting lighter, the tween objects created give alot more freedom to garbage collector DONE
• alot of public methods are no longer public, to simplify the Tween constructor and improve performance DONE
• the tween object will store the prefixed properties if that's the case, to improve performance DONE
• add perspective as a transform object property as already formatted string DONE
• box model props are transformed from % unit to px via element.offsetWidth DONE
• translations are transformed from % unit to px via element.offsetWidth / element.offsetHeight DONE
• rotations and skews are transformed from rad to deg via value * 180/Math.PI DONE
• add all SVG/non-SVG stack transforms and svg path processing into a new crossCheck object DONE
• apply this in all crossCheck functions DONE
• apply this in all parseProperty and prepareStart functions DONE

More updates to come.