Log the result of "git reset --hard".

Use self.runner() instead of run(), so that the result
of running "git reset --hard" is reported and logged.
Clear the build dir before configuring.

Remove any lingering files in the build directory, except
for out-test-baseline subdirectories, needed for "make check".
Merge pull request #13 from jrioux/tests

Clean up as much as possible between runs

Make sure we have a clean build dir before configure/make/make check.

Also, report the result of "git reset --hard" in the log.