func (c *CollisionSystem) New(w *ecs.World) {
	World.SetContactListener(c)
}
New sets the system to the contact listener for box2d, which allows the collision
messages to be sent out.
package engoBox2dSystem
import (
	"github.com/ByteArena/box2d"
	"github.com/EngoEngine/ecs"
	"github.com/EngoEngine/engo"
	"github.com/EngoEngine/engo/common"
)
type CollisionStartMessage struct {
	Contact box2d.B2ContactInterface
}
func (CollisionStartMessage) Type() string { return "CollisionStartMessage" }
type CollisionEndMessage struct {
	Contact box2d.B2ContactInterface
}
func (CollisionEndMessage) Type() string { return "CollisionEndMessage" }
type PreSolveMessage struct {
	Contact     box2d.B2ContactInterface
	OldManifold box2d.B2Manifold
}
func (PreSolveMessage) Type() string { return "PreSolveMessage" }
type PostSolveMessage struct {
	Contact box2d.B2ContactInterface
	Impulse *box2d.B2ContactImpulse
}
func (PostSolveMessage) Type() string { return "PostSolveMessage" }
type collisionEntity struct {
	*ecs.BasicEntity
	*common.SpaceComponent
	*Box2dComponent
}
type CollisionSystem struct {
	entities []collisionEntity
}