Version 0.4

This update has quite a large amount of changes! The emphasis here is on the terrain. 

Here is the full changelog:

1. Changed up the main menu completely - it is now hopefully more readable

2. Added the option to procedurally generate "tiny islands". These are 1-pixel islands of coasts with a chance to appear in the ocean.

3. Added 5 new types of terrain - mountain, hill, desert, snow, and forest.

4. Civilizations cannot immediately expand into this terrain, but are instead limited by technology, providing some natural barriers and more aesthetically-pleasing empires.

5. Updated "Europa" and "Boot World" to have the new terrain types.

6. Replaced procedurally-generated rivers with the option to generate "bodies of water" instead.

7. Added procedural map generation with 7 choices:

     1. Flatlands - similar to the original generated maps, except there are also patches of forest

     2. Islands - generates islands with hills and mountains using Simplex Noise

     3. Lakes - the inverse of Islands - generates "islands" of water in an "ocean" of grass using Simplex Noise

     4. Two Halves - generates two rectangles with water between them

     5. Four Corners - generates four rectangles in each corner of the map, separated by water

     6. Chaos World - completely random placement of terrain, but with some rules applied to it afterwards

     7. Mountain world - grass, hills and mountains

8. The minimum map size is now 25-by-25

9. Added a new quantity attached to Civilizations called "Stability".  It is between 0% and 100%, and will decrease by 0.1% for each 10% of war exhaustion a civilization has.

10. If a civilization reaches 0% Stability and has any vassals, all of them will break free, and the Civilization may also decline in size and change its name(as if to simulate a new government). Civilizations with no internal territories that reach 0% Stability will be deleted.

11. Civilizations no longer have a chance to research, but instead it grows by an amount up to 100%. This "research rate" depends on stability, territorial size, among other things. Vassal civilizations share technology with their overlords, and vice versa.

12. When a civilization is clicked, all of its vassals are colored in Cyan

13. Slightly improved civilizations' procedural name generation

14. Added a "Have grasslands after coast" option, which will procedurally force every coastal territory to have a grassland neighboring it.