Since it generates lots of wheel events, it was re-triggering the bouncer
animation before it was completed. The result was a 'jittering' (d)effect.
I also increased the friction factor to make it scroll slower.
svn path=/trunk/KDE/kdelibs/; revision=1026404
ATM, it uses timers to do the animation, the idea is to use factory pattern
and implement the animation with QProperyAnimation too (using Qt 4.6).
svn path=/trunk/KDE/kdelibs/; revision=1024929
