(svn r14582) -Fix [FS#2392]: blank box on cost estimation of levelling a flat area.
-Fix: make levelling, raising and lowering of an area behave the same.
Makefile*
bin/*
!bin/data/chars.grf
!bin/data/openttdd.grf
!bin/data/openttdw.grf
!bin/data/opntitle.grf
!bin/scenario/README
!bin/scripts*
config.*
objs/*
src/rev.cpp