(svn r13674) -Fix [FS#2127]: crash when drawing a non-real sprite. The drawing of the non-real sprite is caused when two NewGRFs replace the same sprite and the first replaces it with a real sprite (and thus assumes it remains a real sprite) and the second replaces it with a non-real sprite. OpenTTD already looked at whether the sprite to load should be seen as a real or non-real sprite, but it failed to replace non-real sprites with a substitute real sprite when getting the sprite from the cache.

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