Merge pull request #352 from meatballhat/handle-signals-in-sleep-loop

Handling signals while "sleeping"
Collapsing lib/resque_scheduler into lib/resque/scheduler

plus oodles of other changes related to the move, wheeeee!
Extracting some of Resque::Scheduler's functionality into modules

although this is admittedly not an awesome solution.  Needs more work.