Convenient GUI for editing imat_fn data attributes.
g=edit_attributes(f)
EDIT_ATTRIUBTES is a convenience Graphical User Interface for editing imat_fn attributes. Most attributes are editable. The GUI groups related attributes for easy editing.
The input argument to EDIT_ATTRIBUTES is an imat_fn. It can be an array of functions. The output G is an imat_fn containing the modified imat_fn. If the user clicks on 'Cancel', then g=-1 is returned.