Battle of Britain remake of PSS game CodeSVN

Message window can be now accessed from within mapa.java class.

Message window is working. Ingame messages can be added and shown in it.

Added options window (for showing radar ranges, opening combat message window etc.).
Added window closing listener to combat message window.

Added combat message window (empty for now). It will show participants and results of all combats.
(Also, closing game window shuts down application - earlier it was still running)

Messages in upper window cleaned up a bit.

Air combat: added combat register. Corrected setting target for squadron (setting target allowed only for squadrons in air, earlier it was possible for squadrons on the ground if they were selected in air first)

Some unfinished work ;-)

Air combat: corrected checking if combat occurs among squadrons. Now German squadrons (not groups yet) can be attacked by multiple British squadrons.

Minor adjustments and planning air combat (comments).

Groups:
- Squadron may have a leader (leading squadron) which it follows (sets the same target as leader's target)
- Leading and following squadrons may occupy the same position (allows to combine fighters with bombers)