Added license file

Added Jungle location. Changed Savanna trader to come 4 times a year, instead of 5 times. Corrected estimated difficulties.

Added North Saharan Oasis location. Changed Tundra trader to come twice a year, instead of once.

Added reindeer to Tundra, as well as a herd of ibex to simulate reindeer domestication by the nomadic reindeer herders.

Added Tundra location. Renamed difficulties.

Removed old versions 4.0 and 3.3, due to "incompatibility" with game version 1.5.1 (a "Duplicate strings.." message was shown when entering game, even if not playing this mod). Saved games of those old versions, if any, might no longer work.

Slightly delayed some enemies not to attack during winter, except for last attack. Also, will attack with steel weapons just a bit sooner.

Quick-fix for some Mountain Valleys houses overlapping, a bug introduced maybe a few updates back.