Proposal for mousewheel events

I propose that we use "mousewheel" for vertical movement and "mousewheelx" 
for horizontal movement, both using the same interface (which would be 
compatible with IE's implementation).

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

ISSUE-56