According to the discussion in #923, it seems like this should be the
only way to fix this encoding debug issue. I'm also going to coordinate
with aws-sdk to get this fix in the upstream.

Fixes #923, #301

* Added test for checking if path gets interpolated correctly without passing
  :path or :url options
* gsub default :rails_root filesystem-like path to nothing for Fog storage,
  just like in S3 Storage.

`s3_protocol` now returns the protocol without a colon. If you need a
colon, you can pass in `true` as a second argument.

This might not be a best solution, so any better patch that does not
introduce a regression is welcome.

Fixes #921

* Add StyleTokenNotFound in Errors
* Adjust tests to make sure :style present where not currently defined

Also, 3.1.0 and 3.1.1 will be yanked because of the regression.

@mvz caught this in 90ea9dab.
Thank you!

This will solve an issue when using Paperclip without Active Record
such as Mongoid.

Fixes #919

This is for Rails 3.1+

Fixes #902

Fixes #883

Re-fix of #838, #766, #911

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.

This relates to #817

`#reverse_merge` did not work as planned because :default key was
already existed in the hash.

Actually trying to check what's being used in the method instead of
checking for something and use another thing. Thanks @jferris.

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