mdwref.dtx: Add a useful output-formatting hook. Rather than have `\xref@@' produce the output directly, because it's very hairy and hard to replace, have it call a new macro, `\formatxfref', to actually put the pieces together. This can be overridden comfortably, even by novices. Have the default `\formatxref' notice that `hyperref' is available and do use its fancier features to include the category name in the link.
Eliminate tabs from TeX input files. TeX doesn't typeset them very well (despite efforts to address this in `sverb') and Emacs does well enough at dealing without that I've made it display angry fruit salad when it sees tabs in TeX source. So the tabs in the source files have to go.
mdwtab.dtx: Cope when \if@leqno is frobbed dynamically. Thanks to Christian Cornelssen for this change. I considered adding user commands for twiddling \if@leqno (and \if@fleqn), but I decided against it because the `leqno' and `fleqn' options do a notionally document-class-specific thing which (in common cases) involves a complicated rewrite of the `equation' environment and the \[...\] commands, which I really don't want to get into right now.