Remove unnecessary SCP (Save Cursor Position)

It is reported that it can have an unwanted side effect of clearing the
screen on terminal emulators that do not properly support it.

Patch suggested by @arya.

Close #1011

src/tui/light.go

@@ -209,7 +209,9 @@ func (r *LightRenderer) Init() {
 	r.csi(fmt.Sprintf("%dA", r.MaxY()-1))
 	r.csi("G")
 	r.csi("K")
+	if !r.clearOnExit && !r.fullscreen {
 		r.csi("s")
+	}
 	if !r.fullscreen && r.mouse {
 		r.yoffset, _ = r.findOffset()
 	}