Improve URL generation in lyrics plugin
Improve URL generation in lyrics plugin

Allow custom replacements to be defined in subclasses of
SymbolsReplaced.

Replace spaces with a hyphens when the source is MusiXmatch, instead of
(incorrectly) using underscores. This fixes #1880.

swt30/beets,artemutin/beets,pkess/beets,sampsyo/beets,xsteadfastx/beets,artemutin/beets,lengtche/beets,madmouser1/beets,jackwilsdon/beets,ibmibmibm/beets,pkess/beets,swt30/beets,SusannaMaria/beets,MyTunesFreeMusic/privacy-policy,Freso/beets,pkess/beets,lengtche/beets,ibmibmibm/beets,mosesfistos1/beetbox,mried/beets,shamangeorge/beets,Kraymer/beets,Kraymer/beets,sampsyo/beets,diego-plan9/beets,jcoady9/beets,beetbox/beets,ibmibmibm/beets,sampsyo/beets,Kraymer/beets,xsteadfastx/beets,MyTunesFreeMusic/privacy-policy,diego-plan9/beets,jcoady9/beets,mried/beets,Kraymer/beets,diego-plan9/beets,artemutin/beets,jcoady9/beets,pkess/beets,xsteadfastx/beets,mried/beets,swt30/beets,Freso/beets,SusannaMaria/beets,jackwilsdon/beets,MyTunesFreeMusic/privacy-policy,madmouser1/beets,shamangeorge/beets,Freso/beets,sampsyo/beets,lengtche/beets,mosesfistos1/beetbox,mosesfistos1/beetbox,mried/beets,madmouser1/beets,beetbox/beets,xsteadfastx/beets,mosesfistos1/beetbox,jackwilsdon/beets,ibmibmibm/beets,jcoady9/beets,SusannaMaria/beets,beetbox/beets,shamangeorge/beets,beetbox/beets,SusannaMaria/beets,lengtche/beets,shamangeorge/beets,Freso/beets,diego-plan9/beets,madmouser1/beets,MyTunesFreeMusic/privacy-policy,jackwilsdon/beets,artemutin/beets,swt30/beets