Adjust layout.py algorithms to use float32 data by default.
Adjust layout.py algorithms to use float32 data by default.

Fix shell_layout return value

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extra : convert_revision : svn%3A3ed01bd8-26fb-0310-9e4c-ca1a4053419f/networkx/trunk%401156

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