Add graphviz back since it is used by the CS188x class.
Add graphviz back since it is used by the CS188x class.

CredoReference/configuration,leansoft/configuration,usernamenumber/configuration,jp-bpl/configuration,Livit/Livit.Learn.EdX.configuration,antshin72/configuration,EDUlib/configuration,Softmotions/configuration,appsembler/configuration,gsehub/configuration,zhengjunwei/configuration,joshhu/configuration,CredoReference/configuration,xiangjf/configuration,CredoReference/configuration,hks-epod/configuration,fghaas/edx-configuration,rue89-tech/configuration,knehez/configuration,gashac03/ubuntu,yrchen/configuration,usernamenumber/configuration,alu042/configuration,antshin72/configuration,jp-bpl/configuration,antshin72/configuration,Carlos2005/configuration,stvstnfrd/configuration,edx/configuration,pedrorib/istx,antoviaque/configuration,pobrejuanito/configuration,eduStack/configuration,kursitet/configuration,kursitet/configuration,kursitet/configuration,4eek/configuration,appsembler/configuration,jorgeomarmh/configuration,nunpa/configuration,jp-bpl/configuration,IndonesiaX/configuration,leansoft/configuration,fghaas/edx-configuration,louyihua/configuration,Softmotions/configuration,louyihua/configuration,Pieros/configuration,AlfiyaZi/configuration,nikolas/configuration,antshin72/configuration,open-craft/configuration,xiangjf/configuration,zhengjunwei/configuration,hastexo/edx-configuration,antoviaque/configuration,Pieros/configuration,beacloudgenius/configuration,Livit/Livit.Learn.EdX.configuration,openfun/configuration,beacloudgenius/configuration,eduStack/configuration,knehez/configuration,glengal/configuration,xiangjf/configuration,pedrorib/istx,lgfa29/configuration,openfun/configuration,4eek/configuration,marcore/configuration,beacloudgenius/configuration,stvstnfrd/configuration,Pieros/configuration,Softmotions/configuration,marcore/configuration,hastexo/edx-configuration-old,Stanford-Online/configuration,fghaas/edx-configuration,stvstnfrd/configuration,hastexo/edx-configuration,appsembler/configuration,edx/configuration,arbrandes/edx-configuration,hks-epod/configuration,CredoReference/configuration,joshhu/configuration,hks-epod/configuration,4eek/configuration,cyanna/configuration,jp-bpl/configuration,hastexo/edx-configuration-old,pedrorib/istx,lgfa29/configuration,rue89-tech/configuration,EDUlib/configuration,EDUlib/configuration,proversity-org/configuration,mitodl/configuration,nttks/configuration,arifsetiawan/configuration,Stanford-Online/configuration,hastexo/edx-configuration,arbrandes/edx-configuration,nttks/configuration,vasyarv/configuration,marcore/configuration,armaan/edx-configuration,knehez/configuration,open-craft/configuration,Carlos2005/configuration,openfun/configuration,hastexo/edx-configuration,Pieros/configuration,eduStack/configuration,zhengjunwei/configuration,mitodl/configuration,nikolas/configuration,open-craft/configuration,omarkhan/configuration,edx/configuration,4eek/configuration,nttks/configuration,cyanna/configuration,arbrandes/edx-configuration,glengal/configuration,armaan/edx-configuration,michaelsteiner19/open-edx-configuration,gsehub/configuration,IndonesiaX/configuration,bugcy013/edx_infra,gsehub/configuration,gashac03/ubuntu,alu042/configuration,rue89-tech/configuration,vasyarv/configuration,Stanford-Online/configuration,louyihua/configuration,Carlos2005/configuration,armaan/edx-configuration,bugcy013/edx_infra,jorgeomarmh/configuration,lgfa29/configuration,gashac03/ubuntu,antoviaque/configuration,EDUlib/configuration,kursitet/configuration,hastexo/edx-configuration,jp-bpl/configuration,vasyarv/configuration,glengal/configuration,omarkhan/configuration,proversity-org/configuration,fghaas/edx-configuration,mitodl/configuration,kencung/configuration,kencung/configuration,nunpa/configuration,IndonesiaX/configuration,Carlos2005/configuration,nunpa/configuration,bugcy013/edx_infra,yrchen/configuration,appsembler/configuration,gsehub/configuration,beacloudgenius/configuration,xiangjf/configuration,Stanford-Online/configuration,yrchen/configuration,proversity-org/configuration,alu042/configuration,joshhu/configuration,kencung/configuration,Livit/Livit.Learn.EdX.configuration,hastexo/edx-configuration-old,Livit/Livit.Learn.EdX.configuration,armaan/edx-configuration,michaelsteiner19/open-edx-configuration,open-craft/configuration,antoviaque/configuration,glengal/configuration,leansoft/configuration,cyanna/configuration,AlfiyaZi/configuration,Stanford-Online/configuration,openfun/configuration,AlfiyaZi/configuration,edx/configuration,proversity-org/configuration,nikolas/configuration,proversity-org/configuration,Softmotions/configuration,zhengjunwei/configuration,arbrandes/edx-configuration,kencung/configuration,lgfa29/configuration,joshhu/configuration,leansoft/configuration,nikolas/configuration,pobrejuanito/configuration,michaelsteiner19/open-edx-configuration,alu042/configuration,bugcy013/edx_infra,hks-epod/configuration,gsehub/configuration,EDUlib/configuration,arbrandes/edx-configuration,mitodl/configuration,pedrorib/istx,arifsetiawan/configuration,omarkhan/configuration,usernamen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