The zero(), one(), and half() functions weren't documented, and aren't used anywhere...

The zero(), one(), and half() functions weren't documented, and aren't used anywhere, but half() was returning a quarter rotation, and one() was returning a half rotation.  Surely they're both meant to return twice that?  Fixed accordingly, and commented them.

git-svn-id: http://svn.voria.com/code@788 1f10aa63-cdf2-0310-b900-c93c546f37ac