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

Resolve  - don't crash for ByteBuffer byte errors

Game saves are regular json, not minimalized json 

AI civilian improvement: Don't freeze when enemy is near, keep working in tiles where he can't reach

Units that can enter foreign lands without open borders are not expelled on open borders end

Population icon gets locked with doubleclick, clicks cycle between assigned and unassigned 

By SomeTroglodyte:
- Fix ConcurrentModificationException when puppeting a city 
- Next-Turn Progressbar 
- Resolve To-do in Unit upgrade resource requirements