add imgui support

include/client/states/ImGuiDrawer.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <NazaraImgui/ImguiHandler.hpp>
+
+namespace blitz {
+namespace client {
+
+class ImGuiDrawer : private Nz::ImguiHandler {
+  protected:
+	ImGuiDrawer();
+	~ImGuiDrawer();
+
+	virtual void OnRenderImgui() = 0;
+};
+
+}  // namespace client
+}  // namespace blitz