add comment to browser.js, style.js and support.js
fix bug of zero duration. and change internal design
avoid to extend String object. using str custom function.
can use more array format. 
e.g. 
rotate: [45, 45]
rotate: [45, 45, 45]
to: [100, 0]
to: [100, 0, 100]
scale: [2, 2]
scale: [2, 2, 2]