Aabb2.centerAndHalfExtents constructor

Aabb2.centerAndHalfExtents(Vector2 center, Vector2 halfExtents)

Create a new AABB with a center and halfExtents.

Implementation 

factory Aabb2.centerAndHalfExtents(Vector2 center, Vector2 halfExtents) =>
    new Aabb2()..setCenterAndHalfExtents(center, halfExtents);