GL: make lwjgl implementation classes final

jme3-core/src/main/java/com/jme3/renderer/opengl/GL.java

@@ -161,6 +161,7 @@ public interface GL {
         public static final int GL_TEXTURE_CUBE_MAP_NEGATIVE_Y = 0x8518;
         public static final int GL_TEXTURE_CUBE_MAP_POSITIVE_Z = 0x8519;
         public static final int GL_TEXTURE_CUBE_MAP_NEGATIVE_Z = 0x851A;
+        public static final int GL_TEXTURE_BASE_LEVEL = 0x813C;
 	public static final int GL_TEXTURE_MAG_FILTER = 0x2800;
 	public static final int GL_TEXTURE_MAX_LEVEL = 0x813D;
 	public static final int GL_TEXTURE_MIN_FILTER = 0x2801;

jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglGL.java

@@ -13,7 +13,7 @@ import java.nio.ShortBuffer;
 import com.jme3.renderer.opengl.GL4;
 import org.lwjgl.opengl.*;
 
-public class LwjglGL implements GL, GL2, GL3, GL4 {
+public final class LwjglGL implements GL, GL2, GL3, GL4 {
     
     private static void checkLimit(Buffer buffer) {
         if (buffer == null) {

jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglGLExt.java

@@ -13,7 +13,7 @@ import org.lwjgl.opengl.GL15;
 import org.lwjgl.opengl.GL20;
 import org.lwjgl.opengl.GLSync;
 
-public class LwjglGLExt implements GLExt {
+public final class LwjglGLExt implements GLExt {
 
     private static void checkLimit(Buffer buffer) {
         if (buffer == null) {

jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglGLFboEXT.java

@@ -13,7 +13,7 @@ import org.lwjgl.opengl.EXTFramebufferObject;
  * 
  * @author Kirill Vainer
  */
-public class LwjglGLFboEXT implements GLFbo {
+public final class LwjglGLFboEXT implements GLFbo {
 
     private static void checkLimit(Buffer buffer) {
         if (buffer == null) {

jme3-lwjgl/src/main/java/com/jme3/renderer/lwjgl/LwjglGLFboGL3.java

@@ -11,7 +11,7 @@ import org.lwjgl.opengl.GL30;
  * 
  * @author Kirill Vainer
  */
-public class LwjglGLFboGL3 implements GLFbo {
+public final class LwjglGLFboGL3 implements GLFbo {
 
     private static void checkLimit(Buffer buffer) {
         if (buffer == null) {