associated with Bug 1087414 - added time machine class

Bug 1087414 describes a situation where we have a discontinuity between a set of crashes' "date_processed" and their actual date of submission.  This PR introduces a Processor Rule that when used as the only rule in a Processor2015 instance can resolve the problem.  

It turns the processor into a special type of reprocessing processor.  Using an SQL query instead of RabbitMQ to know what crashes to process, the processor will take these steps for each crash:
* load the processed crash that already exists in HB
* alter the 'date_processed', decrementing it by a configurable time delta
* log the action in the processor notes, preserving the old processor notes
* save the processed crash back to PG, HB and ES

After using this processor on the crashes with the bad date, backfilling the materialized views will correct the stats for the affected days.