Battle of Britain remake of PSS game CodeSVN

Added ActionListeners to buttons in Airfield menu

Selected squadron is bordered in cyan.
Added crosshair indicating actual target of squadron.

Airfield menu: when airfield is selected, window is displayed with list of squadrons. Added buttons and scrolling list of squadrons to airfield menu

displays window with list of landed squadrons when airfield is selected

added displaySquadron in Airfield class - returns numbers of squadrons which are landed on selected airfield

** NOT WORKING PROPERLY ** trying to add displaySquadron in Airfield class. Window pop-ups when airfield is selected. It should also check which squadrons are landed on selected airfield. It doesn't paint or move squadrons which are landed (as should be)

Added selection of airfield, radar station and city (squadron selection was added earlier)
Display name of airfield, radar station number, name of city when mouse is over it (info about squadron was added earlier)

Corrected: course setting and moving squadron.
Changed circling over target. Now after reaching target it turns around and flies back to earlier position, then again to target and so on - not stays in place over target as before. It is needed because of adding collision detection.
Added collision detection. Squadron can't move into position occupied by another squadron, no matter friendly or hostile.

Minor adjustments in Mapa.java (preparing to add selection of airfields, cities and radar stations)

Minor adjustments to squadrons' movement: squadrons can't go off map now and when they reach target they start circling over it instead of getting 0 degrees course