use heapq instead of queues.Priority in single_source_dijkstra
use heapq instead of queues.Priority in single_source_dijkstra

--HG--
extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%40310

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