Adds error logging on bad shader node input
Adds error logging on bad shader node input

jtorresfabra/osgjs,gideonmay/osgjs,cedricpinson/osgjs,hishamabdelrahman/osgjs,jtorresfabra/osgjs,gideonmay/osgjs,gideonmay/osgjs,cedricpinson/osgjs,jtorresfabra/osgjs,cedricpinson/osgjs,hishamabdelrahman/osgjs,hishamabdelrahman/osgjs