Allow payloads that have custom keys but no alerts or badges
Merge pull request #44 from overlycommonname/master

Allow Notifications with no alert or badge, but which do have a custom payload
Bump to version 0.3.3
Add NotificationHelpers to DRY-up/simplify specs

Use a common helper to exract the payload hash and payload bytes.
fix newsstand notification payload
Merge branch 'khelll-master'
Clean up formatting; clarify class comment