converted constants in ColorBarWidget to attributes
converted constants in ColorBarWidget to attributes

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