test, provide some more regression files for the invariants of adjustment

The idea was that the arithmetic mean corresponds to a total-payout adjustment
(which is the default), whereas the geometric mean corresponds to a total-return
adjustment.

The diagrams:

      +------mean(P1,P2)--- M
     /\                     |
    /  \                    |
   P1  P2                   |
    |   |                   |
   adj adj      <=>        adj
    |   |                   |
   P1' P2'                  |
    \  /                    |
     \/                     |
      +----mean(P1',P2')--- A

are commutative for adj = total-return and mean = geometric,
and adj = total-payout and mean = arithmetic.

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'test/invariants'

* test/invariants:
  test, provide some more regression files for the invariants of adjustment
doc, provide man page (help2man gen'd) for cattle

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
doc, chore, skip referring to info page in man page

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
chore, PEBKAC, list cattle.ggo as SOURCE so help2man would work

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'doc/man'

* doc/man:
  chore, PEBKAC, list cattle.ggo as SOURCE so help2man would work
  doc, chore, skip referring to info page in man page
  doc, provide man page (help2man gen'd) for cattle
fix, PEBKAC, remove gen'd files for the invariant regression

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'test/invariants'

* test/invariants:
  fix, PEBKAC, remove gen'd files for the invariant regression