show mosto messages in header

  - The li element for every message was at the same level of the ul, so
    for KB / KO it was outside the scope of the foreach binding, causing
    the error "ReferenceError: message is not defined".

  - Also, we tried to applyBindings() multiple times on self.el and that
    doesn't quite work, if it does at all. For now I moved the messages
    view inside the master view together with app and framestatus.

    What we could do in the future is to bind individually to
    .now-playing-block, .show-block, etc. instead.