Wow, so it turns out that didSelectRowAtIndexPath is no longer correct in Swift 3. The correct usage is now didSelectRowAt. I didn't see this mentioned anywhere except thisthis question which I stumbled upon.
This:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { print("You selected cell #\(indexPath.row)!") } Not This:
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath){ print("You selected cell #\(indexPath.row)!") }