revert back to css inlet hover animation, and customize the animation for each style (still needs more work, though)

try replacing css animation with web animation API (this will be more flexible once we pull the xlet highlighting logic out of the c code)

Added transformed dx/dy for scalar "drag" events. This can be revisited if it turns out to be a CPU hog.

 shows as selected when in a gop.

(selective port-- didn't include the logic related to the x_selected member
*fixed bug reported by Gilberto in http://disis.music.vt.edu/pipermail/l2ork-dev/2015-January/000676.html