fix ancient issue with hedgehogs sliding through/into think gaps; fixes
issue #542; could and should be optimized (also to make sure that hogs can't slide through little pixel turds) - feel free to do so =P
More flagging of Land values. Also use less than for tests of non-terrain, instead of "and $FF00 = 0". Saves a couple of ops, which actually matters a small amount in a few places.
barebone cmake config file to support pascal files, based off plplot's ada files
Key returned 0 for arrows under linux. Sym works, clearer anyway.