added persistent errors and clearerror
added persistent errors and clearerror

--HG--
extra : convert_revision : svn%3A41726ec3-264d-0410-9c23-a9f1637257cc/trunk%40170

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