New online multiplayer no longer stuck when first player is human spectator

Modding:
- Replaced old religion style actions! Paves the way for unit action generalization
- Mod checker displays *all* unknown uniques

By SomeTroglodyte:
- Pedia pixel units
- Fix top bar layout
- City overview restore fixed header

Apply conditionals for free buildings to the destination city instead of the originating city  - By SeventhM

Test city conquest functions  - By Framonti