Changed mimetype guessing
Changed mimetype guessing

First look in system-known extensions/types through `mimetypes` module,
then in supysonic configuration

nwokeo/supysonic,ezpuzz/supysonic,nwokeo/supysonic,spl0k/supysonic,spl0k/supysonic,hhm0/supysonic,nwokeo/supysonic,nwokeo/supysonic,hhm0/supysonic,ezpuzz/supysonic,nwokeo/supysonic,hhm0/supysonic,spl0k/supysonic