When ColumnFactory.packColumn() uses the TableHeader renderer to get the width
of the column header, it does not pass the column index to the renderer.
Instead, it always passes 0.
This is a problem for me because I have a custom table header renderer that
displays icons in some columns and text in others. Without being given the
correct column index, the wrong header width is frequently obtained.
BTW, packColumn() should probably be made more generic. It doesn't depend on
JXTable or TableColumnExt so there is no reason to require arguments of these
classes (i.e. replace JXTable w/ JTable).