Merge pull request #124 from wilg/master

Fall back to ActiveSupport::Logger for Rails 4.0.0.rc1 support
Decouple the storage backend.
Fix 2.0 failure.
Remove commented code.
Reflect on GCM canonical IDs. Fixes #123.
Initialize store in Rapns.push
time_to_live no longer requires collapse_key
Update changelog [ci skip].
3.3.0
Update readme [ci skip].
Allow nested hashes in notification attributes
Merge pull request #128 from perezda/master

Allow nested hashes in notification attributes.
Merge pull request #1 from ileitch/master

merge master