consolidate configuration information
Morpho currently has configuration info about schemas, layout, and help hints
spread across at least 4 types of configuration files (config.xml, package
wizard config files, xml editor config files, and dtds). There may also be some
hardcoded stuff in the code. Need to consolidate allof this information into
one easy to use configuration scheme. This will probably involve using xml
schema docs directly to extract information. We should however maintain a
distinction between schema configuration (dtd/schema) and layout configuration.
I'm not sure we currently maintain this difference well.