Identify cycling

Clicking on `Cycle' will cause the row label of one point after
another to be displayed, and the associated case profile plot will
be updated as well.

`Change Direction':  Clicking here causes the direction of the
cycling to change.   That is, if the cycling routine is working
upward through the row numbers, it will start to work downward, and
vice versa.

`All pts' or `Brushed pts':  The default is that the routine cycles
through all points.  If `Brushed pts' is selected, the routine will
instead cycle through only brushed points.  That is, no matter how
many different colors and glyphs have been used, only the points in
the default glyph and color will be skipped.