Return None in 'get_track_image' when r.status_code not ok.
Return None in 'get_track_image' when r.status_code not ok.

meska/SoCo,lawrenceakka/SoCo,flavio/SoCo,bwhaley/SoCo,dundeemt/SoCo,fgend31/SoCo,simonalpha/SoCo,petteraas/SoCo,petteraas/SoCo,xxdede/SoCo,xxdede/SoCo,xxdede/SoCo,jlmcgehee21/SoCo,dajobe/SoCo,TrondKjeldas/SoCo,fxstein/SoCo,SoCo/SoCo,TrondKjeldas/SoCo,meska/SoCo,oyvindmal/SocoWebService,lawrenceakka/SoCo,KennethNielsen/SoCo,oyvindmal/SocoWebService,KennethNielsen/SoCo,flavio/SoCo,petteraas/SoCo,TrondKjeldas/SoCo,bwhaley/SoCo,intfrr/SoCo,simonalpha/SoCo,SoCo/SoCo,intfrr/SoCo,jlmcgehee21/SoCo,dsully/SoCo,bwhaley/SoCo,dsully/SoCo,fgend31/SoCo,dajobe/SoCo,dundeemt/SoCo,DPH/SoCo,DPH/SoCo,fxstein/SoCo