Added embedded Spotify player

Spotify URIs will now create shell links and an embedded copy of the
linked media to be launched directly from within the channel or private
message.
Emoticon and Spotify player improvements

The Spotify player is now instantiated by both the Spotify URIs and HTTP
links generated by the share option in Spotify.

Improved the regular expressions used to detect whether to show
emoticons or not to prevent emoticons being used incorrectly in cases
such as links and code samples that people are sending via IRC.
Added a setting to toggle using embedded media
Added embedded YouTube player

YouTube links that appear in a channel or private message will now
automatically generate an embedded copy of the video if the embedded
media setting is enabled.
Tidied up media embedding code

Moved the code to embed YouTube and Spotify media into their own
functions.
Merge pull request #21 from rastating/feature/embedded-media

feature/embedded-media