Log Message:
Update ruby-mime-types to 3.0.

== 3.0 / 2015-11-21

* 2 governance changes

  * This project and the related mime-types-data project are now exclusively
    MIT licensed. Resolves
    {#95}[https://github.com/mime-types/ruby-mime-types/issues/95].

  * All projects under the mime-types organization now have a standard code of
    conduct adapted from the {Contributor
    Covenant}[http://contributor-covenant.org]. This text can be found in the
    {Code-of-Conduct.rdoc}[Code-of-Conduct_rdoc.html] file.

* 3 major changes

  * All methods deprecated in mime-types 2.x have been removed.
  * mime-types now requires Ruby 2.0 compatibility or later. Resolves
    {#97}[https://github.com/mime-types/ruby-mime-types/issues/97].
  * The registry data has been removed from mime-types and put into
    mime-types-data, maintained and released separately. It can be found at
    {mime-types-data}[https://github.com/mime-types/mime-types-data].

* 17 minor changes:

  * MIME::Type changes:

    * Changed the way that simplified types representations are creatd to
      reflect the fact that +x-+ prefixes are no longer considered special
      according to IANA. A simplified MIME type is case-folded to lowercase. A
      new keyword parameter, +remove_x_prefix+, can be provided to remove +x-+
      prefixes.
    * Improved initialization with an Array works so that extensions do not
      need to be wrapped in another array. This means that <tt>%w(text/yaml
      yaml yml)</tt> works in the same way that <tt>['text/yaml', %w(yaml
      yml)]</tt> did (and still does).
    * Changed +priority_compare+ to conform with attributes that no longer
      exist.
    * Changed the internal implementation of extensions to use a frozen Set.
    * When extensions are set or modified with +add_extensions+, the primary
      registry will be informed of a need to reindex extensions. Resolves
      {#84}[https://github.com/mime-types/ruby-mime-types/issues/84].
    * The preferred extension can be set explicitly. If not set, it will be the
      first extension. If the preferred extension is not in the extension list,
      it will be added.
    * Improved how xref URLs are generated.
    * Converted +obsolete+, +registered+ and +signature+ to attr_accessors.

  * MIME::Types changes:

    * Modified MIME::Types.new to track instances of MIME::Types so that they
      can be told to reindex the extensions as necessary.
    * Removed +data_version+ attribute.
    * Changed #[] so that the +complete+ and +registered+ flags are keywords
      instead of a generic options parameter.
    * Extracted the class methods to a separate file.
    * Changed the container implementation to use a Set instead of an Array to
      prevent data duplication. Resolves
      {#79}[https://github.com/mime-types/ruby-mime-types/issues/79].

  * MIME::Types::Cache changes:

    * Caching is now based on the data gem version instead of the mime-types
      version.
    * Caching is compatible with columnar registry stores.

  * MIME::Types::Loader changes:

    * MIME::Types::Loader::PATH has been removed and replaced with
      MIME::Types::Data::PATH from the mime-types-data gem. The environment
      variable RUBY_MIME_TYPES_DATA is still used.
    * Support for the long-deprecated mime-types v1 format has been removed.
    * The registry is default loaded from the columnar store by default. The
      internal format of the columnar store has changed; many of the boolean
      flags are now loaded from a single file. Resolves
      {#85}[https://github.com/mime-types/ruby-mime-types/85].