Fix for mouse actions in other windows affecting OR (e.g. right-click drag rotates OR's view).
Add Shift/Control modifiers to mouse rotation speed and reduce normal speed.
Change mouse cursor to always disappear, even when popups open.
git-svn-id: http://svn.uktrainsim.com/svn/openrails/trunk@706 a9f3cfff-6c41-7446-b0ca-052bd761e6eb