Fixed frigorie to use calorie.short

I appear to have added this in "Miscellaneous upheaval and additions to archaea"
a few years back, and stuff worked, but the Object() inheriting from the _short
that shall become calorie.short no longer seems to behave well as a Quantity :-(

Shuffled the documentation a bit, so that calorie.__doc__ is home to all of the
generic commentary.
Massage Object's borrowing to make Quantity._scale_units_() work.

Also document the various problems Ovject runs up against.
Make more pervasive use of _scale_units_() in Quantity.

This should ensure more consistent success when borrow()ing from Quantity
objects.
More modernisation: less use of apply().