Added a watchtower set piece variation for the medieval through industrial eras.
Added ARTERA_SAILOR_POSTANTIQUE to facilitate this. Thanks to JNR for his advice.
Changed to a smaller base obstruction profile, which allowed for the following:
Removed manual clutter items from the bases for forest, jungle, and marsh.
Consolidated jungle and forest improvements into a single improvement. Differences were negligible without the need for manual clutter.
Consolidated snow and tundra improvements into a single improvement. Colonel Snowman is on both.
Added machine-translated language support for Italian, Korean, Polish, Portuguese, and Spanish.
Pruned unneeded assets