Batched APNs.
Rescue StandardError in the Delivery classes.
Merge branch 'apns-batching'

Conflicts:
	lib/rpush/daemon/apns/delivery.rb
Complete APNs batching.
New Monitor based approach to interruptable sleep.
Wakeup the Feeder when we trap HUP.
Fix rubocop warnings.
require rubocop
Bundle tweaks
Guard style all the things.
Deprecate batch_storage_updates.
Implement retries for Redis. Fixes #47.
DRY functional specs a little.
Perform APNs error handling asynchronously. Fixes #7.
Deprecate check_for_errors.
Use rbx-2
Fix specs
More fixes.
Increase timeout.
Default sound to 'default'.