Changes:
- template_structure_economic.xml is no longer conquest critical, instead of individually at farmstead, market, storehouse (cf. template_structure_resource.xml)
- healers are no longer conquest critical
- fishing boats are no longer conquest critical
- merchant ships are no longer conquest critical
For comparison: (land) traders are currently not conquest critical either (unchanged)
Besides, it's quite annoying to have to hunt for a non-combatant, which can neither build nor attack, abandoned somewhere.