GUI should display empty matrices with "[]" instead of "..."

[Rik]

11/6/13

All,

For empty matrices in the GUI I think it would be nicer to show the value
field as "[]" instead of "...".  The triple dot notation is used whenever
the value is not scalar, and therefore can't be displayed in one line.  An
empty matrix has dimensions, but they aren't relevant and it should just be
shown as empty.  I filed a bug report here
(https://savannah.gnu.org/bugs/?40499).

--Rik