fix for
https://github.com/increpare/PuzzleScript/issues/55

I'm pretty sure it doesn't break anything, but this is actually difficult to automatically test for (the current test probably didn't break in the old version).
imperfect, but
https://github.com/increpare/PuzzleScript/issues/94
edited readme text for demo directory
fixed dropswap demo
https://github.com/increpare/PuzzleScript/issues/95