remove `clear` arg from SceneCanvas.draw_visual
remove `clear` arg from SceneCanvas.draw_visual

hronoses/vispy,RebeccaWPerry/vispy,sbtlaarzc/vispy,QuLogic/vispy,sbtlaarzc/vispy,ghisvail/vispy,kkuunnddaannkk/vispy,sh4wn/vispy,sh4wn/vispy,julienr/vispy,jay3sh/vispy,drufat/vispy,hronoses/vispy,inclement/vispy,hronoses/vispy,Eric89GXL/vispy,bollu/vispy,bollu/vispy,inclement/vispy,srinathv/vispy,jdreaver/vispy,michaelaye/vispy,QuLogic/vispy,srinathv/vispy,jay3sh/vispy,drufat/vispy,drufat/vispy,ghisvail/vispy,michaelaye/vispy,RebeccaWPerry/vispy,dchilds7/Deysha-Star-Formation,Eric89GXL/vispy,sh4wn/vispy,ghisvail/vispy,dchilds7/Deysha-Star-Formation,bollu/vispy,dchilds7/Deysha-Star-Formation,inclement/vispy,kkuunnddaannkk/vispy,jay3sh/vispy,michaelaye/vispy,sbtlaarzc/vispy,srinathv/vispy,jdreaver/vispy,Eric89GXL/vispy,kkuunnddaannkk/vispy,jdreaver/vispy,QuLogic/vispy,julienr/vispy,RebeccaWPerry/vispy,julienr/vispy