Touch ups and additional capabilities added to fifo functionality. Sample Fenrir scripts in extra

uiterm/ui_regression_test.go

@@ -43,3 +43,21 @@ func TestSafeRuneRemovesTerminalControlCharacters(t *testing.T) {
 		t.Fatalf("safeRune altered printable text: %U", got)
 	}
 }
+
+func TestDispatchCommandReportsMatchesAndPreservesArguments(t *testing.T) {
+	ui := New(nil)
+	got := ""
+	ui.AddCommandListener(func(_ *Ui, command string) {
+		got = command
+	}, "record")
+
+	if !ui.DispatchCommand("record start") {
+		t.Fatal("registered command was not handled")
+	}
+	if got != "start" {
+		t.Fatalf("command argument = %q, want start", got)
+	}
+	if ui.DispatchCommand("unknown") {
+		t.Fatal("unknown command was reported as handled")
+	}
+}