Make sure we don't index past the end of the array

MatterControl.OpenGL/GCodeRenderer/GCodeRenderer.cs

@@ -342,7 +342,8 @@ namespace MatterHackers.GCodeVisualizer
 				for (int i = renderInfo.EndLayerIndex - 1; i >= renderInfo.StartLayerIndex; i--)
 				{
 					// If its the first render or we change what we are trying to render then create vertex data.
-					if (layerVertexBuffer[i] == null)
+					if (layerVertexBuffer.Count > i
+						&&  layerVertexBuffer[i] == null)
 					{
 						layerVertexBuffer[i] = Create3DDataForLayer(i, renderInfo);
 					}

Submodules/agg-sharp

@@ -1 +1 @@
-Subproject commit cebbbccd825b282a1a322271246a4603810c4e31
+Subproject commit 6e36de975620da1f06daefbd082cccecb8a927d6