Added onStop callback for some special cases.

See https://github.com/sole/tween.js/issues/99 for more details.
13dev!
whitespacing
correcting name of method >_<
Add tests for onStop callback functionality
fixing all the spacing.
TOC for the user guide
CSS where is better.
No jank example 04-using CSS transform instead of changing left property
docs: what is a tween
docs: animating / update parameters
docs: controlling the tweens
docs: controlling all the tweens
docs: changing the easing and customising easing
Refactor example 3's createGraph function to external file, in order to use it in the new example 12 for custom easing functions.
Example 12: More custom easing functions!
Example 12: random is random
docs: callbacks
update contributor username
Merge pull request #110 from fundon/update-contributor-username

Update contributor username