superclass vs superCategory

[<eric@son-of-blob>]

Ravi used the method 'fetchSuperCategory' in the converter module, which
was the first one I encountered in the translation.  To the alpha-5 xpp, I
installed Category * Category::fetchSuperCategory().  Actually, the I'm
putting the newest additions to xpp in ~eric/xu/alpha-5/newerxpp which will
be frozen as a release after all the additions that people currently need.
This directory has only the non-translated part.  If you're feeling brave,
you can use this directory for your *.hxx files.  Since there aren't too
many changes going on with it right now, its dtext/dt is low.
	- e -