Upgrade HikariCP to 1.3.8 (deprecated minimumPoolSize changes to minimumIdle).
Add Brett Wooldridge to Contributors list
Remove exclusion of commons-logging.
Revert "Remove exclusion of commons-logging."

This reverts commit d09656cd85e3043ff1ae1a476f482e16d07986ab.
Clean up build logic around using a consistent version of slf4j and not using commons-logging.
Merge branch 'upgrade-hikari'