massaged message files

also, begged the player not to misuse the save-game feature for cheating
prettified (?) the routes
Merge pull request #151 from jvoigtlaender/routes

prettified (?) the routes
Merge pull request #150 from jvoigtlaender/messages

massaged message files
Fix #152 in aibenchmark.
Display ship outlines as rounded rectangles. (addresses #153)
added key generator (see #125)
legend icon for sunk ship is now also rounded