implemented error handling for invalid, non-key/value cli argumnets
implemented error handling for invalid, non-key/value cli argumnets

pkess/beets,SusannaMaria/beets,beetbox/beets,sampsyo/beets,shamangeorge/beets,sampsyo/beets,jackwilsdon/beets,beetbox/beets,shamangeorge/beets,shamangeorge/beets,ibmibmibm/beets,jackwilsdon/beets,pkess/beets,ibmibmibm/beets,jackwilsdon/beets,beetbox/beets,sampsyo/beets,SusannaMaria/beets,SusannaMaria/beets,shamangeorge/beets,SusannaMaria/beets,pkess/beets,ibmibmibm/beets,sampsyo/beets,jackwilsdon/beets,pkess/beets,beetbox/beets,ibmibmibm/beets