Comment 1 for bug 703442

Animated the play-head and play-head line to the cursor position when the
ruler is clicked. When the ruler is dragged (i.e. scrubbed) it does not animate.
Also, when the video is playing, it does not animate. This is to prevent uneven
and stuttering play-head movement. But in general, whenever
a drag operation on the ruler is started (or a click) the play-head smoothly animates
the position of the cursor. I really like the way it feels.

Also, sped up the delay in the video thread. This results in higher CPU, but
smoother play-head movement as it moves across the timeline.