remove dead code from visuals/colorbar
remove dead code from visuals/colorbar

kkuunnddaannkk/vispy,jdreaver/vispy,inclement/vispy,RebeccaWPerry/vispy,QuLogic/vispy,jdreaver/vispy,QuLogic/vispy,julienr/vispy,michaelaye/vispy,RebeccaWPerry/vispy,dchilds7/Deysha-Star-Formation,Eric89GXL/vispy,drufat/vispy,drufat/vispy,ghisvail/vispy,RebeccaWPerry/vispy,inclement/vispy,ghisvail/vispy,srinathv/vispy,drufat/vispy,dchilds7/Deysha-Star-Formation,ghisvail/vispy,Eric89GXL/vispy,michaelaye/vispy,julienr/vispy,kkuunnddaannkk/vispy,julienr/vispy,jdreaver/vispy,kkuunnddaannkk/vispy,Eric89GXL/vispy,inclement/vispy,bollu/vispy,dchilds7/Deysha-Star-Formation,bollu/vispy,srinathv/vispy,bollu/vispy,srinathv/vispy,michaelaye/vispy,QuLogic/vispy