Added settings for circles vs hexagons for movable tiles

Modding:
- Added 'civ checkcountable' console command
- Trigger 'on tile enter' before removing barb camps / ruins
- Suggest conditional order in uniques, for performance
- Harden unique parameters to disallow negative numbers where not relevant

Eureka unique - By EmperorPinguin

By SomeTroglodyte:
- Improve save file name and errors handling
- Better Countable handling

Fix untranslated strings - By Ouaz