cmd: add --progress-terminal-title to print ETA to terminal title

Adds a flag, --progress-terminal-title, that when used with --progress,
will print the string `ETA: %s` to the terminal title.

This also adds WriteTerminalTitle to lib/terminal

cmd/cmd.go

@@ -36,6 +36,7 @@ import (
 	"github.com/rclone/rclone/fs/rc/rcflags"
 	"github.com/rclone/rclone/fs/rc/rcserver"
 	"github.com/rclone/rclone/lib/atexit"
+	"github.com/rclone/rclone/lib/terminal"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -289,6 +290,11 @@ func Run(Retry bool, showStats bool, cmd *cobra.Command, f func() error) {
 	}
 	fs.Debugf(nil, "%d go routines active\n", runtime.NumGoroutine())
 
+	if fs.Config.Progress && fs.Config.ProgressTerminalTitle {
+		// Clear terminal title
+		terminal.WriteTerminalTitle("")
+	}
+
 	// dump all running go-routines
 	if fs.Config.Dump&fs.DumpGoRoutines != 0 {
 		err := pprof.Lookup("goroutine").WriteTo(os.Stdout, 1)