• Some support for gather statistics has been added to Model (see Model::set_gather_statistics()). If requested, an API can be provided so that the individual data points can be returned to programs.

• A class RigidBodyDistancePairScore has been added which provides accelerated computations for the distance between two rigid bodies.

• The swig input files were renamed from swig.i to swig.i-in to aid in dependency tracking.

• rigid bodies now have two sets of particles associated with them in the various places they are used. One is the RigidBodyMember particles, as was previously the case. The other is defined through a refiner (and could be the RigidBodyMember if a RigidMembersRefiner is used). The idea is that you sometimes want some particles which are transformed along with the rigid body, but which are not really part of the representation of the rigid body. Examples would include marker points or multiresolution representations of proteins.The RigidMembersRefiner is generally provided as a default, so the API doesn't change.