reverting an unneded change
A small but useful modification in the ChContact class: when restitution coefficient is used, the object does not rebounce prematurely if the distance to the surface is not closer than (approaching speed * timestep). PReviously, in case of large collision envolope, it could cause 'bouncing' over the coll.envelope.
Founding of the Python module for wrapping the unit_FEM. Not yet functional, it is a stub to check basic functionality.