Converted CleanupSignupsJob into a sidekiq worker.
Conveted DestroyOldJobStatesJob into a Sidekiq worker.
Converted DestroyUserJob into a Sidekiq worker.
When exporting subscriptions in OPML format, order feeds by title.

This makes the OPML more readable and, perhaps more important, makes order deterministic which helps testing. Some intermittent problems testing this feature should go away.
Converted ExportSubscriptionsJob to a Sidekiq worker.
Converted FixSchedulesJob into a Sidekiq worker
Converted ImportSubcriptionsJob into a Sidekiq worker.
Converted RefreshFeedJob into a Sidekiq worker
Converted ScheduledUpdateFeedJob into a Sidekiq worker.

Some tests now fail because for the moment the old Resque job is being enqueued from the app, instead of the new Sidekiq worker.
Converted SubscribeUserJob to a Sidekiq worker.

Currently some tests are failing, because they are querying Resque to ask for enqueued jobs. When the tests are changed to use Sidekiq's testing API instead, they will pass again.
Converted UnsubscribeUserJob to a Sidekiq worker
Converted UpdateFeedUnreadCountJob to a Sidekiq worker