Updating GSAP to 1.9.6

- Fixes an issue that could cause callbacks not to fire if they are placed at the VERY beginning of a TimelineMax and it repeats. (recent regression)

- Fixes an issue in CSSPlugin that could cause x/y portions of transforms to be reverted to 0 in a rare scenario, only in IE8 and earlier.

- Adds ability for directional rotation suffixes to be combined like "20_cw_short" or "30_ccw_short" so that you can go in a particular direction but prevent it from going around more than once.