Add new code to handle the raise/down of pantographs: P controls the aft pantograph, shift-P controls the front pantograph. Moved code related to pantograph to MSTSWagon.cs.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@714 a9f3cfff-6c41-7446-b0ca-052bd761e6eb