physical element of dataTable element should be optional
Currently, any data package containing a dataTable element which does not itslef contain a physical element will not open properly in Morpho. When attempting to open, several error boxes which the message "physical list is null!" will appear, after which the window where the dp would open will simply remain gray with the butterfly flapping indefinitely. The physical element is optional in EML, so Morpho should be able to open these dp's.