Unciv: 3.18.17

From Unciv: link to the original post

3.18.17

Handling for multiplayer download errors

Fixed fringe-case crashes

By xlenstra:

• Fixed a bug that occasionally placed hills on top of mountains
• Made all the other constants determining the strength of cities moddable
• Fixed a bug where citadels did not damage nearby units
• Updated the natural wonders for vanilla

Fix incorrect Archer obsolete - By AdityaMH