Accelerated mousewheel scrolling in Firefox and possible fix for unrecognized mousewheel scrolling (all browsers)

Scrolling tempo was too slow compared no normal mousewheel scrolling in Firefox.

See http://forums.enyojs.com/discussion/600/scrolling-strategies  for more info about second commit.

Enyo-DCO-1.0-Signed-off-by: Martin Borho martin@borho.net