Add PyGLy documenation link to README.md.
Add PyGLy documenation link to README.md.

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