#3 method to mark item as "in progres"

[Luke Schierer]

I'd like to be able to mark items as "in progress" so
that a .todo file being used by multiple developers can
also indicate which items are being worked on and which
are available for anyone to start on w/out duplicating
effort. the closest to this i see right now is marking
something "done" but that's not ideal as things that
seems to be for something that has been completed.