Sanitize terminal widget text

uiterm/view.go

@@ -1,5 +1,16 @@
 package uiterm
 
+import "unicode"
+
+// safeRune prevents text supplied by a server or another user from being
+// interpreted as a terminal control sequence when termbox flushes its cells.
+func safeRune(r rune) rune {
+	if unicode.IsControl(r) || unicode.Is(unicode.Bidi_Control, r) {
+		return ' '
+	}
+	return r
+}
+
 type View interface {
 	uiInitialize(ui *Ui)
 	uiSetActive(active bool)