Known bugs:
-----------
* Setting 0 rows and 0 columns results in a very large width.

* Adding columns when zero rows and adding rows when zero columns could
  do with a bit of work.

* It seems the prototype declarations for XmDrawHighlight() and bcopy() 
  are missing from some OS's and thus compilations may complain of an implicit
  declaration of these functions.

* When resizing columns and the shadow is drawn over both fixed rows and
  non fixed rows, if you look *really* closely, the join in the line does
  not match up perfectly.

* When deselecting or selecting columns that are clipped, any fixed rows
  are partially blanked.

* Two undocumented public functions XbaeMatrixYToRow() and XbaeMatrixXToCol()
  exist but don't work correctly for fixed rows / columns.
