- IMP::core::ClosePairsPairScore has been split into IMP::core::ClosePairsPairScore and IMP::core::KClosePairsPairScore as the previous version encompassed two different, easily confused, behaviors. It now is accelerated and takes advantage of rigid bodies. The constructor signature was changed to force you to revisit code that might be affected by the behavior changes. IMP::core::RigidBodyDistancePairScore is now just a wrapper on IMP::core::KClosePairsPairScore.

- IMP::atom::Selection was added to facilitate representation independent setup of restraints and manipulation of hierarchies. Check it out.

- a new, more involved example, kernel/examples/nup84_cg was added, blatantly ripping off Elina's restrainer nup84 example