add showcase on several updating possibilities of IsocurveVisual
add showcase on several updating possibilities of IsocurveVisual

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