screencap fix

vene.cpp

@@ -244,7 +244,7 @@ extern "C"
 
 	void vene_screenshot(const Arg*)
 	{
-		Cmd scrot("scrot", "-s");
+		Cmd scrot("scrot", "-s", "-");
 		Cmd tee("tee", SCREEN_CAPS_DIR);
 		Cmd xclip("xclip", "-selection", "clipboard", "-t", "image/png");
 		scrot | tee | xclip; // todo: cppipe < string