function GestureHandler (name) {
  this.name = name;
  this.state = {};
}
MdGestureHandler
A GestureHandler is an object which is able to dispatch custom dom events
based on native dom {touch,pointer,mouse}{start,move,end} events.

A gesture will manage its lifecycle through the start,move,end, and cancel
functions, which are called by native dom events.

A gesture has the concept of 'options' (eg. a swipe's required velocity), which can be
overridden by elements registering through $mdGesture.register().