clean up nested_viewbox example
clean up nested_viewbox example

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