Fix 4.0a unresponsive zoom and swipes on multimap 1-3
To be checked carefully before committing to 4.0 branch!
Expecially, the risk is that we generate an event while for example in M1, and while it is drawing M1 we change to infopages, or any other mapspace, and the event is passed to the new mapspace even if it was originally triggered for the M1,
	modified:   Draw/Multimaps/DrawMultimap_Asp.cpp
	modified:   Draw/Multimaps/RenderAirspace.cpp
	modified:   Draw/Multimaps/RenderNearAirspace.cpp