Update print-failure and print-error to handle various output formats.

- Add a format argument to print-failure
- Convert print-error to a generic function
- Add a format argument to print-error
- Add a global variable *output-format*
Merge branch 'master' into assertion-records

Conflicts:
	lisp-unit.lisp
Preliminary implementation of comprehensive test results objects.
Organize the main lisp-unit file.
Update print-failure to work with result objects.
Update print-error to work with result objects.
Properly handle the extra results.
Print failures and errors during tests if requested.
Print failures and errors as test results are generated.
Refine and export the failure and error print functions.
Use the local exerr in print-errors.
Reset the global counters whenever run-tests or run-tags is called.

Results are pushed to the global counters whenever assertions are
directly evaluated. These counters cannot, should not, be used directly,
so it is a good idea to reset them periodically. A good time to do that
is when run-tests or run-tags is called.
Update %run-thunks to make a test-results-db instance.
Resurrect the use-debugger function.

A victim of over-zealous factoring.
Merge branch 'master' into assertion-records

Conflicts:
	lisp-unit.lisp
Clean up the equality predicates.
Warn if there are no tests for a tag.
Examples of using tags.
README for version 0.9.3.
FIXME note for the norm of an array in the floating point extensions.