(svn r13352) [0.6] -Backport from trunk (r13348, r13222, r13221, r13217):
- Fix: Industry tiles would sometimes tell they need a 'level' slope when they do not want the slope (r13348)
- Fix: Attempts to make the old AI perform better (r13217, r13221, r13222)

You can place you scenarios in this dir.

This file is really here to make the Makefile happy, it should be modified to
properly handle scenarios (or maybe even not at all...).