[Feature] Method to remove physics body

[IRobot1]

NgtPhysicBody provides methods to create physics bodies. However, looking at the code, the only place/time physics bodies are deleted is when the canvas is disposed.

Can you add a method to remove a body at runtime?

[nartc]

Added in latest version under the PhysicBodyApi as remove() and at(index).remove(). I'll check out the PRs soon