Media Monitor: tell all handlers when a device status changes to MEDIASTAT_OPEN

This changes the media monitor to tell all handlers when a devices status
changes to MEDIASTAT_OPEN even if that handler doesn't support the current
media type.

This is necessary because the media type sometimes changes to MEDIATYPE_UNKNOWN
when a CD is ejected for example so the music media handler never gets to know
the CD has been ejected because it is only set to handle MEDIATYPE_AUDIO.