Document MDA and other advanced Copper features.

[schwerdf]

Currently, the Copper user manual covers only those features accessible from the CUP skin. Beyond what appears in the Javadoc and my thesis, the modular determinism analysis and other advanced features (parse table composition, etc.) are undocumented.

Attempts to produce this documentation in the past have been stymied by the fact that the features are only accessible through the XML skin and Java API, which were not meant to be used directly. However, if we regard the Javadoc for the grammarbeans package as suitably documenting the API, some usable documentation could be produced.