Implement some suggestions by Laura Creighton.

Implement some suggestions by Laura Creighton.

ChipWidget.__init__(): Added a message area just below the color
    name.  Both the message and name widgets are now FLAT, DISABLED
    Entry widgets instead of Labels.  This allows users to
    copy-n-paste the color names or color specs.  Also, the contents
    of both widgets are now driven by StringVars.

set_color(): This only sets the chip color; it does not set the name
    widgets.

set_name(): New method which only sets the name widget contents.

set_message(): New method which only sets the message widget contents.

ChipViewer.update_yourself(): Set the color, name, and message for
    each chip as follows: the first line always contains the color
    spec in #rrggbb format.  The second line will contain the color
    name, but slightly differently for each widget.  For the Selected
    widget, if the color exactly matches the Nearest color, the name
    is shown, otherwise the message field will be empty.  The name
    field of the Nearest widget will always contain the color name.