Schema writing superfluous groupURI field

[aclarkxyz]

The root node should not emit groupURI, e.g.

{
    "schemaPrefix": "http://www.bioassayontology.org/bas#",
    "root": 
    {
        "name": "common assay template",
        "descr": "The Common Assay Template is designed to capture most of the high value data from in vitro assays, particularly those used for high throughput screening.",
        "groupURI": "",
        "assignments": 

... is given as blank. It should not be added as a field, because it is never defined. Only descendent groups can have a groupURI.