fix typo.

src/materials/MeshPhongMaterial.js

@@ -69,7 +69,7 @@ THREE.MeshPhongMaterial = function ( parameters ) {
 	this.map = null;
 
 	this.lightMap = null;
-	this.lightMapIntensity = null;
+	this.lightMapIntensity = 1.0;
 
 	this.aoMap = null;
 	this.aoMapIntensity = 1.0;