Add little documentation comments.

I'll be using DDoc or some sort of documentation generation utility and
standard. I just think it's overkill at this point.
Fix bugs, complete things and change the style.

This takes a slight preference for using `input.function` rather than
`function(input)` and fixes things which were implemented but left
unused (namely `redoPath(target)`). It also checks to see if the target
has any `redoPath` and fails gracefully if it doesn't.