[IMP-dev] Nonbonded list try 2

Here is the next crack at submitting the nonbonded list. Something is undoubtedly missing.

The changes since the last submission include - the grid is now updated lazily. A MaxChangeScoreState is used to accomplish this. That class just keeps track of the max change of a set of variables - various bugs have been fixed

Already forgot something

These changes to IMP.i may or may not be needed %pythonprepend NonbondedListScoreState::add_bonded_list %{ args[1].thisown=0 %} %pythonprepend NonbondedRestraint::NonbondedRestraint %{ args[1].thisown=0 %} %pythonprepend BondDecoratorRestraint::BondDecoratorRestraint %{ args[1].thisown=0 %}