Add AbsOEmbedParser for parsers based on oEmbed

Also adds jackson-core for JSON processing.
Add Deviantart parser
Tweak AbsOEmbedParser to support content urls
Add Flickr parser
Refactor structure to make it more concise and DRY

Leverages the hierarchy more.
Don't print oEmbed exceptions due to missing values
Add Hulu parser
Add Justin.tv parser
Add rdio and spotify parsers
Add Screenr parser
Add SlideShare parser
Add SoundCloud parser
Add Ted parser
Update README with the new supported services