Many still import (chibi), and as (scheme base) is somewhat more
expensive to load at present these are changed to cond-expand.
Many libraries also rely on (srfi 33), and these have been changed
to a cond-expand first trying (srfi 60) where available.
Also fixing a few portability concerns (duplicate imports of the
same binding), and adding a few libraries missing from lib-tests.scm.
By convention, a library meant for testing exports "run-tests".
Also by convention, assume the test for (foo bar) is (foo bar-test),
keeping the test in the same directory and avoiding confusion since
(chibi test) is not a test for (chibi).
- Avoids the hack of "load"ing test, with resulting namespace complications.
- Allows keeping tests together with the libraries.
- Allows setting up test hooks before running.
- Allows implicit inference of test locations when using above conventions.
