Convert all PyGraphviz (swig) objects to Python objects when converting to NetworkX graphs.
Convert all PyGraphviz (swig) objects to Python objects
when converting to NetworkX graphs.

Fixes #213.

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extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%401096

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