Multimap 2 empowered: better printed values on screen as boxed overlays, and final glide MC overlay.

The new small boxed indicator is showing the maximum MC value and its relative airspeed to get over the destination with a 0m arrival altitude.

Cleaned up the code a bit, but essentially no changes otherwise.
	modified:   ../Draw/Multimaps/RenderAirspace.cpp
Fix 4.0a safety altitude overlay indicator not appearing when using multimaps.
New customkey Reset View . It will instantly bring screen to moving map , and reset all infopages to the first.

	modified:   ../../Data/Language/ENG_MSG.TXT
	modified:   ../../Data/Language/ToDo.TXT
	modified:   ../../Header/LKInterface.h
	modified:   ../Dialogs/AddCustomKeyList.cpp
	modified:   LKCustomKeyHandler.cpp
fix previous commit for empowered M2, using overindex for FinMc.
	modified:   RenderAirspace.cpp
Remove LD from M2 and shorter target name on overlay
	modified:   RenderAirspace.cpp