A New era of the map generators

New generators:

• Chaos - full randomness;
• Corners - an epic battle with many cities in the center;
• Donut - balanced map with a lake in the center and the sea on the sides.

Reworked River generator for 4 people

Now all of the players is separated from the others by rivers.

Bug Fix

• Fixed a bug with cities on islands that were not taken into account when calculating income;
• Fixed a bug with incorrect camera movement when destroying the player's base.