Some performance or memory optimizations

Replaced String concat in loops with StringBuilder (performance)
Replaced for with keySet + Map.get() through for with entrySet (perf)
Changed inner classes to static classes, mostly struct like (memory)

src/main/java/appeng/client/render/RenderBlocksWorkaround.java

@@ -23,7 +23,7 @@ public class RenderBlocksWorkaround extends RenderBlocks
 	public EnumSet<ForgeDirection> renderFaces = EnumSet.allOf( ForgeDirection.class );
 	public EnumSet<ForgeDirection> faces = EnumSet.allOf( ForgeDirection.class );
 
-	private class LightingCache implements ISimplifiedBundle
+	private static class LightingCache implements ISimplifiedBundle
 	{
 
 		public IIcon rXPos;