DEVS: Fix problem with aircraft overlapping each other at bases/sites/havens

[Muton]

One of the few annoying things is the common occurrence when you're two aircraft are sitting there at your base or a haven etc and they are right over each other. overlapping.. You click and you cant seem to get the other plane selected... Using the Aircraft screen and clicking the location button does not select that aircraft, just finds the location with the other plane selected. Sometimes you have to press the right/left arrow and cycle through the 19 aircraft I have till it lands on the one I want. 5 bases X 2 + 9 LotA sites