Spawning a rigidbody at the same position as another

[unravel-dev]

Hi again. I am spawning 2 spheres rigidbodies at the same location. For some shapes this is defined for some it isn't and i get an assert
Example spawning 2 boxes at the same location seems to work and they seem to push eachother away which seems ok.
When spawning 2 spheres for example at the same location gets an assert here

create_contact_point
...
    EDYN_ASSERT(length_sqr(rp.normal) > EDYN_EPSILON);

i am wondering if edyn should handle this case and define some behavior instead of just bailing when the 2 bodies are at the same position.

[xissburg]

Yes it should be able to handle these situations. This can be fixed.

[xissburg]

This commit should fix it
3c0a362