Investigate adding Media Library + Adapters

It might be worth adding the media library panel and some adapters which allow it to get data from different sources. BrowserFS provides an adapter for dropbox support. And I'm willing to write an adapter for mStream.

Some services that could be potentially integrated:

* Cloud File storage: Dropbox and Google Drive
* Selfhosted Servers: mStream, Subsonic, Ampache
* Music Streaming Services: Soundcloud, Spotify, Etc
* A Local File System Adapter

This kind of integration would give users a reason to use webamp for everyday music listening