Ditched celery beat in favor of much simpler "Advanced Python Scheduler"

* All periodically executed tasks moved to scheduler.py, which can be run as an upstart task similar to powerpool
* Payouts are now not triggered by block finds, but just processed for all blocks every 60 seconds
* A decorator for all tasks was added that logs to the cache runtime and last exec time for future addition to a debugging view on the site
* Transaction confirmation crontab was removed completely in favor of using the RPC method for confirming transactions
* An unhandled exception in block confirmation code is now properly handled