Update generate-stackbrew-library.sh to handle multiple versions (and prep for adding -onbuild variations)
Update generate-stackbrew-library.sh to handle multiple versions (and prep for adding -onbuild variations)

infosiftr/docker-iojs,hmalphettes/docker-iojs,jbhannah/docker-iojs,Starefossen/docker-iojs,docker-library/node,nodejs/docker-iojs,cgvarela/docker-iojs,pesho/docker-iojs,yyolk/docker-iojs-graphicsmagick,bnadim/docker-iojs