Aether.Physics2D v1.6

Aether.Physics2D is a 2D physics Engine.

In this Release:

• Fix Body.Revolutions (Thanks @jaimeadf!)
• Thread safe events/callbacks
• The following properties are now read-only collections:
  Body.FixtureList, World
  World.BodyList
  World.JointList
  World.ControllerList
• Added Joint.World property
• Added DebugViewFlags.None flag
• The following methods/properties were marked obsolete:
  Body.IslandIndex
  Body.SetRestitution(...)
  Body.SetFriction(...)
  Body.SetCollisionCategories(...)
  Body.SetCollidesWith(...)
  Body.SetCollisionGroup(...)
  Body.SetIsSensor(...)
• The following methods/properties were Removed
  World.IsStepping (Deprecated in version 1.3)
  World(AABB span) (Deprecated in version 1.5)
  World.QueryAABB(ref AABB aabb) (Deprecated in version 1.5)
  World.RayCast(Vector2 point1, Vector2 point2) (Deprecated in version 1.5)
  World.TestPointAll(Vector2 point) (Deprecated in version 1.5)