Battle of Britain remake of PSS game CodeSVN

Bingo fuel: doesn't allow to select target other than airfield when on bingo fuel. Also minor bugs fixes with searching for closest available airfield.

Bingo fuel: doesn't allow to select airfield that is too far away to fly to

Bingo fuel: doesn't allow to select airfield that is too far away to fly to

Checks for bingo fuel properly. Automatically sets destination to home airfield if bingo fuel is reached. If fuel amount is less than bingo fuel, seeks closest airfield. Doesn't allow to manually change destination by player if squadron has been set to return to airfield because of lack of fuel.

Unstable.
Added checking for bingo fuel and automatix return to home base (or any other base in range if home base is too far away). Need some testing and adjustments, though.

Added delay when squadron is taking off (one pulse to prepare after issuing order to take off).
Fixed issue with returning to previous position when squadron reached its destination (didn't work properly when target was located east of squadron).

Squadrons can land now and only on their side's airfield (British squadrons on British airfields, German sq on Germain airfields - which are non-existent now BTW). Also minor adjustment: right-click without squadron selected acts as left-click (may display info about clicked tile: airfield, radar, city)

Adjusted landing menu (box which appears when you select airfield as a target for squadron)

Clicking airfield when squadron is already selected invokes menu with choice of: landing squadron, circling over airfield, canceling.

Airfield is accessed with double-click now