Don't retry job on obviously permanent errors.
Upgraded Unicorn.
Fix booboo in exception hierarchy.
Upgrade to Bunny 1.3.1.
Gemfile: Update pebbles-river.
Handle socket errors during HTTP.
Don't retry on 503 if there is no Retry-After header.
Fix broken backoff logic.
Handle Bunny::ClientTimeout.
Semi-large rewrite.

* Use Pebbles::River for all queuing. This removes some configuration options and simplifies things like error handling.

* Use Pebbles::River::DaemonHelper to run the daemon. Again, this eliminates some configuration options. Config file is now always config/tootsie.conf, the logging is always done through LOGGER, and the pid file and worker count is specified when running bin/tootsie.

* Retooled logging and notifications. Job notifications are now named tootsie.[event]. There is a config option to use the name "tootsie_completed" for completion events.

* Added support for a dedicated failure queue, with an optional TTL setting.
Set use_legacy_completion_event to true by default, and publish multiple events to preserve backwards compatibility.
Support multiple queues with different worker-count settings.
Remove some outdated information from readme.
Gemfile: Update pebbles-river, bunny.
Gemfile: Update pebbles-river.
Don't create failure queue until actual start.
Ignore invalid jobs.
Catch bad resource URIs.
Remove old obsolete Spawner class.
Remove 'rollbar' gem, move into production group.