Consistent behaviour with units

[davidbowler]

trafficstars

We need to make sure that the units that are set (e.g. General.DistanceUnits) are consistent for both input and output, and are applied to all files and output (e.g. coord_next.dat is always output in Bohr radii).

[davidbowler]

Actually I think that this requires considerable care: we would need to introduce a way to annotate coordinate files with the units they are in, which would in turn require a change of format. This needs thought, and may not ever happen (we may just want units to be in the output file itself).