Natural (without 2-km limitations) heights of terrain.

See http://garagegames.com/community/forums/viewthread/136055 for details.

Demo [level](https://drive.google.com/file/d/0B4G7HDT9STV-ekpiS2hyQUE5LTQ/edit?usp=sharing) and [video](http://youtube.com/watch?v=Kkgmsz7416w).