Fix for 555-BOOM! version 0.5

I've discovered a problem that could affect play on systems other than MacOSX.

If the levels seem to be getting played in a random order, replace the following around line 85 of Code/game.py:

  paths = glob(pat)
  if not tutorial:
    paths = [p for p in paths if not os.path.basename(p).startswith("+")]
  return paths
with
  paths = glob(pat)
  if not tutorial:
    paths = [p for p in paths if not os.path.basename(p).startswith("+")]
  paths.sort() # add this line
  return paths
i.e. insert 'paths.sort()' before returning paths.

(I had always thought that glob() was supposed to return its results sorted, but this doesn't seem to be the case on some Linux systems!)