SCRATCH move icons over to Env, instance proxy model to gui

gui/InstanceProxyModel.h

@@ -0,0 +1,13 @@
+#include "groupview/GroupedProxyModel.h"
+
+/**
+ * A proxy model that is responsible for sorting instances into groups
+ */
+class InstanceProxyModel : public GroupedProxyModel
+{
+public:
+	explicit InstanceProxyModel(QObject *parent = 0);
+
+protected:
+	virtual bool subSortLessThan(const QModelIndex &left, const QModelIndex &right) const;
+};