Move DockRightArranger out of OtherArrangers and modify calcArrangementDifference

Enyo-DCO-1.1-Signed-off-by: Jeremy Thomas <jeremy.thomas@palm.com>
Merge pull request #123 from germboy/master

Move DockRightArranger out of OtherArrangers + modify calcArrangementDifference

Reviewed-By: Ben Combee (ben.combee@palm.com)