B Scale_factor Atom_indices

These parameters encode the rigid body information as given in
Section 5.3.4. `Atom_indices` are the numeric indices
of all atoms in the rigid body, and `Scale_factor` the scaling factor from
system state to body orientation.

For example,

B 5 10 25 30creates a rigid body containing atoms 5, 10, 25 and 30.

Automatic builds 2017-07-19