Changes to AttrGraph to make its behavior same as Graph for remove_nodes_from(), add_edges_from() and edges_iter()
Changes to AttrGraph to make its behavior same as Graph for
remove_nodes_from(), add_edges_from() and edges_iter()

--HG--
extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%401171

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