optionally show forms that correspond to the numbers in test mode

[jonorthwash]

Currently apertium-regtest test has output like this:

$ apertium-regtest -c .-morph test
Corpus 1 of 3: -s plurals-morph
  13/13 (100.0%) tests pass (3/13 (23.08%) match gold)

Corpus 2 of 3: -es plurals-morph
  20/20 (100.0%) tests pass (3/20 (15.0%) match gold)

Corpus 3 of 3: irregular plurals-morph
  22/22 (100.0%) tests pass (2/22 (9.09%) match gold)

All tests pass.

It would be nice if there were a way to have output like morph-test/aq-morphtest to show forms that do and/or don't match gold (or, alternatively, tests that are and/or are not expected).

[jonorthwash]

forms that do and/or don't match gold (or, alternatively, tests that are and/or are not expected).

"alternatively", meaning the user should be able to choose, like in the web interface—not meaning that I'm requesting one or the other feature.