A list of things planned for the future for this module, in no particular
order.  As this is a module I can only work on in my free time, or when I
need something for something else I'm doing, I probably won't get to any
of this as fast as I'd like.  If you'd like to implement anything on this
list, drop me a line first at rra@stanford.edu and then have at it!
Credits will be noted in the README.

 * Support for passing in a sub to add (or the constructor) associated
   with a text file that splits each line into a key and values
   theoretically already exists, but I haven't tested it at *all* yet and
   it isn't documented.

 * A way of removing a specific source from the shadow hash might be nice,
   but we'd have to solve the naming problem.

 * Querying the shadow hash for status would also be nice; things like the
   full source list, the override hash, and the deleted hash could be
   exposed to the intrepid.
