If the embedly-ruby gem is installed, the Embedly provider should use it to make ruby-oembed more awesome!

[metavida]

The ruby-oembed gem doesn't have to be in competition with Embedly's embedly-ruby gem. If the embedly-ruby gem is loaded, ruby-oembed should detect it and use a specialized OEmbed::Providers::Embedly Class that uses the embedly-ruby gem internally. There are several advantages to this setup.

1. Because we use the embedly-ruby gem the list of supported URLs will never be out of date.
2. Because we use ruby-oembed calling OEmbed::Providers.get can resolve oEmbed URLs that aren't registered with Embedly (perhaps because they're private) along side every other oEmbed URL that is supported by Embedly.