fix crash on 0 chroma matches for singleton
fix crash on 0 chroma matches for singleton

MyTunesFreeMusic/privacy-policy,mathstuf/beets,multikatt/beets,lengtche/beets,mosesfistos1/beetbox,Freso/beets,mathstuf/beets,multikatt/beets,mried/beets,jcoady9/beets,gabrielaraujof/beets,LordSputnik/beets,arabenjamin/beets,mried/beets,PierreRust/beets,moodboom/beets,aspidites/beets,MyTunesFreeMusic/privacy-policy,beetbox/beets,swt30/beets,shanemikel/beets,Andypsamp/CODjunit,ibmibmibm/beets,imsparsh/beets,jackwilsdon/beets,jcoady9/beets,artemutin/beets,jmwatte/beets,marcuskrahl/beets,sampsyo/beets,jbaiter/beets,m-urban/beets,pkess/beets,asteven/beets,MyTunesFreeMusic/privacy-policy,madmouser1/beets,kareemallen/beets,tima/beets,moodboom/beets,ibmibmibm/beets,jackwilsdon/beets,sadatay/beets,beetbox/beets,YetAnotherNerd/beets,shamangeorge/beets,sadatay/beets,artemutin/beets,Dishwishy/beets,mosesfistos1/beetbox,ibmibmibm/beets,PierreRust/beets,YetAnotherNerd/beets,andremiller/beets,andremiller/beets,pdf/beets,madmouser1/beets,Kraymer/beets,jackwilsdon/beets,ttsda/beets,Wen777/beets,bj-yinyan/beets,imsparsh/beets,arabenjamin/beets,gabrielaraujof/beets,drm00/beets,Freso/beets,randybias/beets,YetAnotherNerd/beets,Andypsamp/CODfinalJUNIT,ttsda/beets,kelvinhammond/beets,diego-plan9/beets,kelvinhammond/beets,Andypsamp/CODjunit,kelvinhammond/beets,lightwang1/beets,kareemallen/beets,tima/beets,YetAnotherNerd/beets,drm00/beets,Freso/beets,sadatay/beets,pkess/beets,PierreRust/beets,marcuskrahl/beets,swt30/beets,shamangeorge/beets,gabrielaraujof/beets,arabenjamin/beets,parapente/beets,ttsda/beets,ruippeixotog/beets,asteven/beets,krig/beets,diego-plan9/beets,Andypsamp/CODfinalJUNIT,mosesfistos1/beetbox,LordSputnik/beets,arabenjamin/beets,xsteadfastx/beets,marcuskrahl/beets,imsparsh/beets,MyTunesFreeMusic/privacy-policy,diego-plan9/beets,xsteadfastx/beets,pkess/beets,randybias/beets,pkess/beets,lightwang1/beets,krig/beets,mried/beets,lightwang1/beets,marcuskrahl/beets,moodboom/beets,LordSputnik/beets,m-urban/beets,mathstuf/beets,Andypsamp/CODjunit,untitaker/beets,artemutin/beets,madmouser1/beets,tima/beets,shamangeorge/beets,mathstuf/beets,Wen777/beets,kareemallen/beets,kareemallen/beets,dfc/beets,dfc/beets,shamangeorge/beets,bj-yinyan/beets,SusannaMaria/beets,m-urban/beets,andremiller/beets,dfc/beets,xsteadfastx/beets,multikatt/beets,SusannaMaria/beets,parapente/beets,sampsyo/beets,shanemikel/beets,shanemikel/beets,Andypsamp/CODfinalJUNIT,swt30/beets,sadatay/beets,untitaker/beets,ttsda/beets,Dishwishy/beets,ruippeixotog/beets,lightwang1/beets,Andypsamp/CODjunit,bj-yinyan/beets,Dishwishy/beets,drm00/beets,Andypsamp/CODfinalJUNIT,drm00/beets,LordSputnik/beets,diego-plan9/beets,swt30/beets,parapente/beets,jackwilsdon/beets,Kraymer/beets,shanemikel/beets,jayme-github/beets,Kraymer/beets,asteven/beets,krig/beets,sampsyo/beets,multikatt/beets,mosesfistos1/beetbox,kelvinhammond/beets,randybias/beets,untitaker/beets,jmwatte/beets,ruippeixotog/beets,gabrielaraujof/beets,bj-yinyan/beets,Kraymer/beets,Andypsamp/CODfinalJUNIT,ibmibmibm/beets,xsteadfastx/beets,Wen777/beets,beetbox/beets,SusannaMaria/beets,imsparsh/beets,ruippeixotog/beets,pdf/beets,m-urban/beets,asteven/beets,Andypsamp/CODjunit,SusannaMaria/beets,tima/beets,Freso/beets,beetbox/beets,lengtche/beets,lengtche/beets,randybias/beets,dfc/beets,aspidites/beets,Dishwishy/beets,untitaker/beets,moodboom/beets,jmwatte/beets,PierreRust/beets,jcoady9/beets,madmouser1/beets,jayme-github/beets,parapente/beets,jmwatte/beets,sampsyo/beets,jcoady9/beets,artemutin/beets,lengtche/beets,mried/beets,jbaiter/beets