Prevent spewing of errors from Program.draw
Prevent spewing of errors from Program.draw

When program encountered an error when being activated,
the draw method would proceed anyway, resulting in lots
of messages for an error caused by trying things while not
being enabled. This patch turns that off.

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