Terrain doesnt render correctly

The core of this issue was the unlock on the GFXGLTextureObject

Few other bug fixes around setting a texture binding to 0, notice in clear function we now also clear the glprogram and the buffers. This seems to fix most of the warnings around id 131204

This warning was triggered every frame, now it just triggers when a shader expects a texture but none is active.

Engine/source/environment/scatterSky.cpp

@@ -1094,7 +1094,7 @@ void ScatterSky::_render( ObjectRenderInst *ri, SceneRenderState *state, BaseMat
    }
    else
    {
-      GFX->setCubeTexture( 0, NULL );
+      GFX->setTexture( 0, NULL );
       mShaderConsts->setSafe( mUseCubemapSC, 0.0f );
    }