Add normalized operator for point/size.
Add normalized operator for point/size.

Summary: This operator is useful for calculating anchor point position within a view.

Reviewers: O2 Material Motion, #material_motion, O4 Material Apple platform reviewers, chuga

Reviewed By: O4 Material Apple platform reviewers, chuga

Subscribers: chuga

Tags: #material_motion

Differential Revision: http://codereview.cc/D2463

material-motion/material-motion-swift,material-motion/material-motion-swift