Valleyfix

The first sandpits level is up and running with a new tileset, though I kind of did it hastily so it may not be as good as the previous one visually. But hey, whatever works. I wanted someone, preferably @edisonout, to test it and make sure the fix is the correct one because I don't want to work on this for hours only to turn out that the tileset is still too big. 

Fixes #1636