Refactor shared behavior into AbstractAdapter superclass
Added expiring_url method to Fog Storage

IMPORTANT: There is a bug in the current release of Fog (1.3.1) that will
return a broken expiring URL when the bucket name is valid for a subdomain.
This is fixed per https://github.com/fog/fog/pull/857 but not released
in the gem yet. I have added currently FAILING tests for these cases that
should pass when a new Fog is released.
Make temporary fixes and passing tests for Fog bugfix to be released
Remove unneeded file
update rails versions
Add test helper for assert file existence
Rewind tempfiles after get saved to storages

Re-fix of #838, #766, #911
Remove whitespaces
Always convert s3_protocol to string first

Fixes #883
Also make sure that file is rewinded in filestore
Add #close, #closed? delegation to AbstractAdapter
Use ActiveSupport::Delegation to delegate method
Close and unlink tempfiles after flush write

Fixes #902
Use Paperclip sexy migration in the generator
Update sexy migration method names
Add cucumber test for migrations
Add command recorder for our migrations

This is for Rails 3.1+
Update Readme to mention sexy migration
Update NEWS file
Cleanup whitespaces