Made the gram plugin python3 compatible
Made the gram plugin python3 compatible

There were a few things to change. I changed the import to get it
working under python3 for urlopen and used items() instead of iteritems().

andreas-h/pelican-plugins,farseerfc/pelican-plugins,talha131/pelican-plugins,cctags/pelican-plugins,jantman/pelican-plugins,kdheepak89/pelican-plugins,benjaminabel/pelican-plugins,pxquim/pelican-plugins,M157q/pelican-plugins,UHBiocomputation/pelican-plugins,wilsonfreitas/pelican-plugins,cctags/pelican-plugins,farseerfc/pelican-plugins,jantman/pelican-plugins,xsteadfastx/pelican-plugins,if1live/pelican-plugins,M157q/pelican-plugins,mortada/pelican-plugins,danmackinlay/pelican-plugins,MarkusH/pelican-plugins,rlaboiss/pelican-plugins,mikitex70/pelican-plugins,talha131/pelican-plugins,rlaboiss/pelican-plugins,ingwinlu/pelican-plugins,howthebodyworks/pelican-plugins,publicus/pelican-plugins,benjaminabel/pelican-plugins,danmackinlay/pelican-plugins,andreas-h/pelican-plugins,howthebodyworks/pelican-plugins,prisae/pelican-plugins,publicus/pelican-plugins,benjaminabel/pelican-plugins,ingwinlu/pelican-plugins,mitchins/pelican-plugins,gjreda/pelican-plugins,florianjacob/pelican-plugins,UHBiocomputation/pelican-plugins,xsteadfastx/pelican-plugins,mortada/pelican-plugins,pxquim/pelican-plugins,mitchins/pelican-plugins,wilsonfreitas/pelican-plugins,andreas-h/pelican-plugins,pxquim/pelican-plugins,andreas-h/pelican-plugins,if1live/pelican-plugins,florianjacob/pelican-plugins,kdheepak89/pelican-plugins,talha131/pelican-plugins,pestrickland/pelican-plugins,farseerfc/pelican-plugins,talha131/pelican-plugins,jakevdp/pelican-plugins,florianjacob/pelican-plugins,prisae/pelican-plugins,davidmarquis/pelican-plugins,prisae/pelican-plugins,mortada/pelican-plugins,howthebodyworks/pelican-plugins,mikitex70/pelican-plugins,davidmarquis/pelican-plugins,publicus/pelican-plugins,xsteadfastx/pelican-plugins,publicus/pelican-plugins,xsteadfastx/pelican-plugins,ingwinlu/pelican-plugins,rlaboiss/pelican-plugins,florianjacob/pelican-plugins,kdheepak89/pelican-plugins,jakevdp/pelican-plugins,mortada/pelican-plugins,danmackinlay/pelican-plugins,cctags/pelican-plugins,mitchins/pelican-plugins,UHBiocomputation/pelican-plugins,davidmarquis/pelican-plugins,danmackinlay/pelican-plugins,ingwinlu/pelican-plugins,mortada/pelican-plugins,pestrickland/pelican-plugins,gjreda/pelican-plugins,farseerfc/pelican-plugins,MarkusH/pelican-plugins,rlaboiss/pelican-plugins,MarkusH/pelican-plugins,pestrickland/pelican-plugins,pxquim/pelican-plugins,gjreda/pelican-plugins,cctags/pelican-plugins,M157q/pelican-plugins,howthebodyworks/pelican-plugins,mikitex70/pelican-plugins,mitchins/pelican-plugins,if1live/pelican-plugins,talha131/pelican-plugins,benjaminabel/pelican-plugins,jakevdp/pelican-plugins,kdheepak89/pelican-plugins,jakevdp/pelican-plugins,jantman/pelican-plugins,M157q/pelican-plugins,wilsonfreitas/pelican-plugins,wilsonfreitas/pelican-plugins,MarkusH/pelican-plugins,davidmarquis/pelican-plugins,farseerfc/pelican-plugins,gjreda/pelican-plugins,pestrickland/pelican-plugins,mikitex70/pelican-plugins,if1live/pelican-plugins,jantman/pelican-plugins,MarkusH/pelican-plugins,prisae/pelican-plugins,UHBiocomputation/pelican-plugins