-Fix: Account for max_heightlevel when saving heightmaps.

git-svn-id: http://svn.openttd.org/trunk@26983 6aa0318a-3be1-0310-93fa-89fd2396df07
-Fix (r26905) [FS#6134]: Heightlevels must be scaled by number of intervals, not by the value of the highest interval. Otherwise the highest interval becomes non-proportionally small.

git-svn-id: http://svn.openttd.org/trunk@26984 6aa0318a-3be1-0310-93fa-89fd2396df07
-Change: Make settings categories more descriptive.

git-svn-id: http://svn.openttd.org/trunk@26985 6aa0318a-3be1-0310-93fa-89fd2396df07
-Change: Rename 'Advanced Settings' to just 'Settings'.

git-svn-id: http://svn.openttd.org/trunk@26986 6aa0318a-3be1-0310-93fa-89fd2396df07