Merge branch 'ab/tap'

* ab/tap: t/README: document more test helpers t/README: proposed rewording... t/README: Document the do's and don'ts of tests t/README: Add a section about skipping tests t/README: Document test_expect_code t/README: Document test_external* t/README: Document the prereq functions, and 3-arg test_* t/README: Typo: paralell -> parallel t/README: The trash is in 't/trash directory.$name' t/t9700/test.pl: don't access private object members, use public access methods t9700: Use Test::More->builder, not $Test::Builder::Test tests: Say "pass" rather than "ok" on empty lines for TAP tests: Skip tests in a way that makes sense under TAP test-lib: output a newline before "ok" under a TAP harness test-lib: Make the test_external_* functions TAP-aware test-lib: Adjust output to be valid TAP format