TestMipMapGen: Use the non AWT MipMap Generator (Don't depend on jme3-desktop but jme3-core, to run this test on android)

jme3-examples/src/main/java/jme3test/conversion/TestMipMapGen.java

@@ -39,7 +39,7 @@ import com.jme3.scene.Geometry;
 import com.jme3.scene.shape.Quad;
 import com.jme3.texture.Image;
 import com.jme3.texture.Texture;
-import jme3tools.converters.MipMapGenerator;
+import com.jme3.util.MipMapGenerator;
 
 public class TestMipMapGen extends SimpleApplication {