[changed] where available, rpqueue will now use Lua to move delayed tasks from
the time-based priority queue to fifo queues. This should reduce overhead
in all cases, and should drastically improve performance for those that
use large numbers of delayed tasks.
[changed] the version number is now PEP 386/440 compliant.
[added] this changelog that will document updates/changes/improvements in an
easily referenced location.
[fixed] thanks to https://github.com/dmaust , rpqueue added a missing 'redis'
requirement.