Clarify default test length in README.rst
Use DROP TABLE IF EXISTS to avoid error messages on the first
loading of ./init/resultdb.sql.
Fix problem of numerous copies of vmstat and iostat running
forever after being launched by timed-os-stats. On some
platforms (e.g. Debian), killing the parent process ID
of timed-os-stats is *not* enough to cause the child subprocess
to exit!
Improve the kill via process group logic. It's not portable to assume
that the process ID of the Python process is the same as the
process group ID, or that the Python process and its subprocesses
are in their own process group separate from the benchwarmer script.

Break out a separate kill_pg script, to give us a portable way to
kill the timed-os-stats process and its children.
Correct duplicated error message.
Merge branch 'master' into fixes
Typofixes and indent fix.
Establish proper foreign key relationships between the
results tables, using ON DELETE CASCADE for all but the
"timing" table, which should only have transient data.
Remove caveat about entries in other table not being
removed along with "tests" entries, since we have
ON DELETE CASCADE now.
Merge pull request #6 from schmiddy/fixes

Usefully kill vmstat/iostat subprocesses.  Add FKs to the results table.