GF-59604: onScrollStop should be fired when scrolling is actually ended.

When we use mousewheeling, onScrollStop event was called from
TouchScrollStrategy.stop().
However scrolling is not actually ended, so it should not fire
onScrollStop event.

Enyo-DCO-1.1-Signed-off-by: David Um david.um@lge.com
GF-59604: Prevent firing onScrollStop from ScrollMath

ScrollMath.mousewheel() and stabilize() shouldn't fire onScrollStop
event.

Enyo-DCO-1.1-Signed-off-by: David Um david.um@lge.com
Change next release to be 2.4.0 instead of 2.3.1

We've decided that post-2.3.0 API changes will be 2.4.0 instead of
2.3.1 to preserve the 2.3.1 naming for maintaince of the 2.3.0
feature set, so CHANGELOG is updated to indicate this.

Enyo-DCO-1.1-Signed-Off-By: Ben Combee (ben.combee@lge.com)
Merge pull request #646 from DavidUM/GF-59604-davidum

Gf 59604 Firing onScrollStop event when scrolling is actually ended.

Reviewed-By: Ben Combee (ben.combee@lge.com)