This file is for more immediate, but probably more mundane TODO material
than the IDEAS file.

Serialisation:
 * Design a file format for saved L-Systems and a Haskell data structure
   to go along with it. Decide what gets saved and what doesn't.
   Needs at least axioms and productions.
 * Also need to parse and render the file format.
   Parsec, Text.PrettyPrint.HughesPJ, XML?

User Interface:
 * Get menus working, and attach them to serialisation functions.