Webplayer can now handle a basic playlist, pushing multiple songs in the
playlist and passing from one song to another.
Some things that are not yet working:
* Using previous and next buttons and going outside of the playlist
breaks things.
* Random / repeat modes are not yet implemented.
* Playlist is not exposed in the UI at the moment.
* Seeking in a song is not exposed in the UI.
* When playing a song, webplayer does not automatically play the next
one when reaching the end of the song.
Major code review, cleaning the code and adding a lot of comments. Also
implements a separate store to keep entities with a reference count and
garbage collection. This closes#15.
Known issues at the moment are:
* Webplayer is no longer working, it has to be refactored.
* AlbumPage is to be implemented.
Now able to play a single file, in a format supported by your browser.
* Playlists not yet supported.
* Volume is a simple on/off switch.
* Repeat / Random not yet supported.
* Build everything in `public/` folder, to serve only this and avoid
issues with `publicPath` in webpack.
* Moved some icons to FontAwesome and use spinning wheels from
FontAwesome to indicate loading.
* (Very) beginning of a webplayer.
