Who are the two new Avengers?

The two new avengers in the trailer (the girl in red and the boy with silver hair) are Scarlet Witch and Quicksilver. They were prominent members of the Avengers in the comics and have a very long and interesting history there. They're the children of long-time X Men villain Magneto and also happen to be mutants themselves...Heck Wanda is powerful enough to bend reality at her whim in the comics, I wonder what will the film do with her...