fix(buttons): add cleaner buttons to UI
feat(notifications): add window focus on click
refactor(tracklist): factor out track / current track

- track and current track are directives now
- track and user links are directives
- current track is shown on top unless in view
feat(chat): add linky support for chat messages
feat(tracklist): add ability to select and delete tracks

- tracks may be selected via click
- delete is performed when DEL key is pressed

Closes #6