Waypoint labelling tidied

Aircraft:
-Font moved to static, overrideable value

Waypoint:
-Font moved to a static, overrideable value
-fixed position bug caused by incorrect precalculation (w = .../2)
-tidied drawing code
+method will be overriden if changed; checks not needed

TransferWaypoint:
-fixed position bug caused by incorrect precalculation (w = .../2)
-removed redundant commented code
-draws labels assuming circular waypoints (new graphics?)
+detects which airspace is being drawn to, and calculates appropriate
bearing
+old code commented for reversion if square is used; better handling of
corners