JSON Protos: If a Property.fromProto returns undefined, don't set that property
JSON Protos: If a Property.fromProto returns undefined, don't set that property

foam-framework/foam,foam-framework/foam,foam-framework/foam,foam-framework/foam,jlhughes/foam,jlhughes/foam,jlhughes/foam,jlhughes/foam,foam-framework/foam