Fix error handling (add import and adjust messages).
Fix error handling (add import and adjust messages).

Fixes #169

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extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%40801

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