webgl: fixed bug in getElementByPoint(): now picked node is returned only if pickobject is not null or undefined instead of only null
webgl: fixed bug in getElementByPoint(): now picked node is returned only if pickobject is not null or undefined instead of only null

xml3d/xml3d.js,ariyapour/xml3d.js,Fiware/webui.Xml3d.js,CCLDESTY/xml3d.js,xml3d/xml3d.js,Fiware/webui.Xml3d.js,ariyapour/xml3d.js,CCLDESTY/xml3d.js