XO-1.5 video rendering not always smooth

[Mikus Grinbergs]

In the new snow-1.xo Activity, the falling "white spots" are noticeably
jerkier in os64 (XO-1.5) than in os10 (XO-1).

Also, on os64 the (software?) cursor sometimes "flickers" annoyingly.
It is always noticeable in the google-chrome browser (on Sugar), and for
instance in the new version of the cartoonbuilder-7.xo Activity.  In
contrast, the (hardware?) cursor in the Opera browser operates smoothly
in os64 (on Sugar).

mikus