Changed param 'Td' to 'td' since the param has been changed to lowercase in switch statemment

examples/js/loaders/MTLLoader.js

@@ -446,7 +446,7 @@ THREE.MTLLoader.MaterialCreator.prototype = {
 
 					break;
 
-				case 'Tr':
+				case 'tr':
 
 					if ( value > 0 ) {