#3 Trajectory file

[Marcus Martin]

The ability to dump out a "trajectory" file including
only the insertable or swappable atoms and the energy
of interaction of each of these atoms with the rest of
the system. Even better would be to separate that
interaction energy into components where one component
is the
energy of interaction with any fixed atoms and the
other is the energy of interaction with other
insertable/swappable atoms.

Suggested to Marcus Martin by Brian Peterson