libtest/make-test-scaffolding: Generate setup & teardown entries.
libtest: Support testcase-specific setup and teardown functions.
libtest: Simplify the output from the '-l' (list) option.
libtest: Simplify test selection.
libtest: Minor code improvements.
libtest: make a verbosity check more visible.
libtest: Improve the test_driver.1 manual page.
libtest: Align the test_driver(1) manual page with the code.