Bug 1102257 - Store the data cycle interval in the settings file
Bug 1102228 - Improve the data cycling routine

Added several parameters to the cycle_data shell command: cycle-interval (in days),
chunk-size (in number of result sets), sleep-time (in seconds).
I made the cycle_data task a very thin wrapper around the shell command,
there is no more logic in it.
All the queries for data cycling are executed with the retry logic to
handle db deadlocks
Merge pull request #291 from mozilla/bug-1102228-improve-data-cycling

Bug 1102228 improve data cycling