Settings -> Gesture & Motion -> Communication -> Gesture answer - this will allow you to pick up a call in hands-free mode. (Simply move your hand to the left of the phone and then to the right, you will need to test it by yourself to see at which speed you need to do that..)
XDA Developers was founded by developers, for developers. It is now a valuable resource for people who want to make the most of their mobile devices, from customizing the look and feel to adding new functionality. Are you a developer?