By SomeTroglodyte:
- Next-Turn Progressbar
- Fixed crash when puppeting city

Population icon gets locked with doubleclick, clicks cycle assigned-unassigned

Resolved crashes when clicking mod in mod management

AI civilian improvement: keep working in tiles where enemy units can't reach

Prophets are not expelled on open borders end

City-state-owned great merchants can no longer 'conduct trade mission' on their own tiles

Game saves are regular json, not libgdx-specific format