Test: make sure diag prints to standard error
Test: When diag'ing, don't precede blank lines with #
Test: diag about failed tests
Test: Report filename/line number of test failure
Test: Don't precede flunk messages with 'flunk'
Test: Make the program's exit status the # of tests failed

What about if this is > 255? or what if it's the sentinel value
for git bisect skip?
Test: Copy filehandles if we can

This way, a test can mess around with standard output/error
without screwing up tests
Test: Don't interleave diag and TAP output

Don't cross the streams!
Merge pull request #296 from hoelzro/test-better

Test better