* Simplify maker names in plugin menu * Make sure derived models have a name (based on the transform) * Don't start deriving a model from a derived model until the derived model is ready * Tidy up completion management in writable wave file model * Make writable models save/reload correctly from session file (i.e. regenerating from the original transform) * Same for dense 3d models -- don't save the data, just the transform details * Add a comment describing the SV file format