When calculating light parameters, add a check for situations where the scene bounding box is empty (fovy cannot be '0' but atan(0) is 0...)
When calculating light parameters, add a check for situations where the scene bounding box is empty (fovy cannot be '0' but atan(0) is 0...)

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