Move the hash utility routines into it's own package.
Use copy() where appropriate, and re-add the invariant check.
Move horst into it's own package.
Remove the useless consts.go file.
Move wots into it's own package.
Kill off the hashSize parameter.
Move the rest of params into sign.go.
Remove params.go since it's empty now.
Run "go fmt", no functional changes.