You can mass ignore or save one of two ways.
At the top left of your screen you will see a save all button. If you press this all pending contacts will be selected. You can then select to either save or ignore the entire list.
By scrolling through the contact list and tapping the circle on the left hand side of the screen on the desired contacts you will be able to take action on multiple contacts. Once you have selected all the contacts you want, click save or ignore to take action on them.