Introduced SwitchLayer which will form the basis of provided support for varients

src/osgPlugins/ive/SwitchLayer.h

@@ -0,0 +1,19 @@
+#ifndef IVE_SWITCHLAYER
+#define IVE_SWITCHLAYER 1
+
+#include <osgTerrain/Layer>
+#include "ReadWrite.h"
+
+namespace ive
+{
+
+class SwitchLayer : public osgTerrain::SwitchLayer, public ReadWrite
+{
+public:
+	void write(DataOutputStream* out);
+	void read(DataInputStream* in);
+};
+
+}
+
+#endif