Use shell job for terminal callback

Fixes #2529

cmd/micro/micro.go

@@ -388,7 +388,6 @@ func DoEvent() {
 	var event tcell.Event
 
 	// Display everything
-	screen.DrawLock.Lock()
 	screen.Screen.Fill(' ', config.DefStyle)
 	screen.Screen.HideCursor()
 	action.Tabs.Display()
@@ -398,7 +397,6 @@ func DoEvent() {
 	action.MainTab().Display()
 	action.InfoBar.Display()
 	screen.Screen.Show()
-	screen.DrawLock.Unlock()
 
 	// Check for new events
 	select {