Fix bug in node and edge attr handling (including keys). Fixes #507.
Fix bug in node and edge attr handling (including keys).
Fixes #507.

blublud/networkx,kernc/networkx,harlowja/networkx,chrisnatali/networkx,ionanrozenfeld/networkx,andnovar/networkx,blublud/networkx,jcurbelo/networkx,yashu-seth/networkx,nathania/networkx,ionanrozenfeld/networkx,sharifulgeo/networkx,dmoliveira/networkx,sharifulgeo/networkx,kai5263499/networkx,SanketDG/networkx,jfinkels/networkx,debsankha/networkx,jni/networkx,harlowja/networkx,jtorrents/networkx,jni/networkx,bzero/networkx,sharifulgeo/networkx,jni/networkx,JamesClough/networkx,farhaanbukhsh/networkx,tmilicic/networkx,aureooms/networkx,harlowja/networkx,ghdk/networkx,RMKD/networkx,jakevdp/networkx,kernc/networkx,nathania/networkx,jtorrents/networkx,blublud/networkx,OrkoHunter/networkx,jakevdp/networkx,dmoliveira/networkx,dmoliveira/networkx,bzero/networkx,dhimmel/networkx,michaelpacer/networkx,kai5263499/networkx,ghdk/networkx,aureooms/networkx,chrisnatali/networkx,RMKD/networkx,Sixshaman/networkx,NvanAdrichem/networkx,kernc/networkx,ghdk/networkx,nathania/networkx,debsankha/networkx,dhimmel/networkx,bzero/networkx,farhaanbukhsh/networkx,dhimmel/networkx,wasade/networkx,aureooms/networkx,goulu/networkx,RMKD/networkx,ionanrozenfeld/networkx,ltiao/networkx,debsankha/networkx,chrisnatali/networkx,kai5263499/networkx,cmtm/networkx,farhaanbukhsh/networkx,beni55/networkx,jakevdp/networkx