Blah. Naming things is hard.
Move README notes to a WIP changelog entry.
Deprecate JobClass.queue, and the default_priority and default_run_at instance variables.
Avoid an errant deprecation warning.
Note deprecations in the CHANGELOG.
Merge branch 'master' into experimental

Conflicts:
	CHANGELOG.md
Changelog tweaks.
Remove deprecated features.
Indifferentiate isn't used by Locker anymore, so move it into Pool.
Clean up CAST_PROCS a bit.
Have Locker support a nil poll_interval.
Log events inside of Locker.
Expose JobQueue#maximum_size and log it in locker_start.
Log execution of SQL and prepared statements at the debug level.
Log the various things that can happen with a job in a Worker.
Include queue names in the pks handled by JobQueue - it's just simpler.
Make JobQueue#accept? clearer.
Remove a require that's no longer necessary.
Fix a rare case wherein an advisory lock may be left open after a spec run.