Comment fixup, whitespace.
most of v2 in this commit:

- sounds played when a block is dropped.
- walker algorithm changed, will drop blocks closer before
  going diagonal, but still prefer lowest deposit location.
- command overhauled: list, enable and disable worlds.
- falling blocks will now "crush" most plants, but not logs.
- decay to sand even in non-desertlike biomes as long as it
  is underwater, same for clay in non-oceanlike biomes.
- config file now stores all params.
- shorthand '/sed' also gives access to all commands.