pry-debugger doesn't compile on JRuby, and we're really only using that
locally.

Fix inconsistent spacing

Little bugfix in README.md

Base64 encoded data-uris can contain newlines, make sure we handle
them correctly.

Content Type errors were incorrectly being set as an array on the base
attribute rather than being set individually as strings.

Copying attribute validation failures up to the root object breaks the
validate_attachment_presence_matcher when other paperclip validations
have failed.  This fixes this bug.

Also refactored to make the strategy hierarchy clearer

Added the sample .mp4 file from Apple's QuickTime sample page:
http://support.apple.com/kb/ht1425

and memoize type_from_file_command

You can either specifiy :restricted_characters or you can define your
own :filename_cleaner object. This object needs to respond to #call and
takes the filename that will be cleaned. It should return the cleaned
filenme.

Return the default path when the attachment has no remote file