Added deprecation warning for Canvas.on_paint
Added deprecation warning for Canvas.on_paint

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