Fixes #913.

Fixes #913

* Bug fix: Use the new correct Amazon S3 encryption header.
* Bug fix: The rake task respects the updated_at column.
* Bug fix: Strip newline from content type.
* Feature: Fog file visibility can be specified per style.
* Feature: Autonatically rotate images.
* Feature: Reduce class-oriented programming of the attachment definitions.

Rack gets a newline at the end of the content_type in certain instances: 'image/jpeg\r' which causes S3 to be unable to accept the file. Fixes #817

This adds a auto-orient option, which is enabled by default. I believe, most users expect their images to be rotated according to EXIF. The photo I've added to the fixtures was token by myself, I release it to the public domain.

need to call save on the instance, otherwise we'll regenerate files with a new timestamp but the updated_at won't reflect that

Happy pi release!

      3.141592653589793238462643383279
    5028841971693993751058209749445923
   07816406286208998628034825342117067
   9821    48086         5132
  823      06647        09384
 46        09550        58223
 17        25359        4081
           2848         1117
           4502         8410
           2701         9385
          21105        55964
          46229        48954
          9303         81964
          4288         10975
         66593         34461
        284756         48233
        78678          31652        71
       2019091         456485       66
      9234603           48610454326648
     2133936            0726024914127
     3724587             00660631558
     817488               152092096

Reverting this for now. This commit would better be in a minor release,
since it break everyone's application. Going to reopen the ticket and
mark it to be merged in next minor release.

This reverts commit b7b2b843.

Fix syntax error on ruby 1.8.7

This PR allows you to assign a URI object to an attachment. The
attachment is downloaded and saved with a proper content type and
filename based on the path of the URL.

When using the form_for helper in the example, we need to use users_path...

Readme typo fix

When using the form_for helper in the example, we need to use users_path and not user_path (which will point to the show action instead of the create action).

* Fixed tests and functionality for new fog and removed the fixed version from the gemspec
* Set time to 3600 from the current time so expiring actually works

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

Let's keep it as class method, as Rails 3.0.x require migration methods
to be class methods.

This reverts commit 029fe02f.

* 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.