activated city distance map, grant landgrab bonus only for weak neighbors
improved isFreshwater()
do not build a navy for an ocean without enemies
do not build settlers if there are no good plots to settle (breaks savegame compatibility)
small perf fixes for isCoastal() and isFreshwater()
changed logging in GetBestSettlePlot (again)
bugfix for city distance map and cleanup for danger plots. breaks savegame compatibility!
fixed bug which made some hills impassable
fixed danger plots update