Morpho

The layout of the 'tree' part of the XML editor should be changed to put the
tree controls at the top and the default display should be just the existing
nodes in the instance. A button (check box?) should be at the top to expand the
tree to show all those nodes that could be added to the existing instance. [This
is a reversal of the current scheme which has a 'trim' button to eliminate those
empty nodes.]

Also, should look for a way to eliminate the eml 'references' nodes in the tree
to simplify the display. [Replace with referenced values if references appear in
the instance document.]