Add IDebugOverlay interface.

Signed-off-by: aixxe <me@aixxe.net>

include/cstrike/Interfaces/IVDebugOverlay.h

@@ -0,0 +1,8 @@
+#pragma once
+
+class IVDebugOverlay {
+	public:
+		bool ScreenPosition(const Vector& world, Vector& screen) {
+			return GetVirtualFunction<int(*)(IVDebugOverlay*, const Vector&, Vector&)>(this, 9)(this, world, screen) == 0;
+		}
+};