more tests work with ascii-wl-pprint
preliminary implementation of issue #63

No tests exist for the comparison function yet.
In other words, I removed Runner.Example.mkResult and
the replacement has no unit tests.

The default doctestEq is also slightly different with respect to
trailing whitespace, so there is a test failure:

  Main.doctest ignores trailing whitespace when matching test output FAILED
  trailing-whitespace ["Foo.hs"]