Make haml --check work.
Make haml --check work.

It wasn't properly requiring the stringio library.

cmpereirasi/sass,ridixcr/sass,macressler/haml,zaru/sass,liquidmetal/sass,schneems/sass,stanhu/haml,zaru/sass,Iamronan/sass,nazar-pc/haml,schneems/sass,rammy7219/sass,HugoRLopes/sass,antonifs/sass,Andrey-Pavlov/sass,StephanieMak/sass,ridixcr/sass,chriseppstein/haml,keithpitty/haml,purcell/haml,chriseppstein/sass,MetaAshley/sass,mislav/haml,dg1dd1ngs/haml,Iamronan/sass,tangposmarvin/sass,MetaAshley/sass,lmetla/sass,haml/haml,dg1dd1ngs/haml,hcatlin/sass,Industrys/sass,liquidmetal/sass,uniba/hamldoc_ja,Nzaga/sass,Anshdesire/sass,Industrys/sass,Nzaga/sass,amatsuda/haml,nicklima/sass,nickg33/sass,stewx/sass,StephanieMak/sass,14113/sass,saper/sass,tangposmarvin/sass,vio/haml,antonifs/sass,Anshdesire/sass,concord-consortium/haml,sideci-sample/sideci-sample-haml,srinivashappy/sass,oss-practice/sass,PMArtz92/sass,macressler/haml,stanhu/haml,HugoRLopes/sass,modulexcite/sass,askl56/sass,amitsuroliya/sass,lmetla/sass,briangonzalez/sass,Galactix/sass,rammy7219/sass,DanteKaris/sass,stefanpenner/haml,modulexcite/sass,PMArtz92/sass,stewx/sass,tangposmarvin/haml,OrenBochman/sass,DanteKaris/sass,xzyfer/sass,srinivashappy/sass,askl56/sass,nickg33/sass,cmpereirasi/sass,dylannnn/sass,Andrey-Pavlov/sass,haml/haml,haml/haml,danielfein/sass,Ahnita/sass,saper/sass,hcatlin/sass,jaroot32/sass,tenderlove/sass,Ahnita/sass,danielfein/sass,tangposmarvin/haml,srawlins/sass,dylannnn/sass,srawlins/sass,chriseppstein/haml,JuanitoFatas/sass,amitsuroliya/sass,nicklima/sass,keithpitty/haml,baiyanghese/sass,xzyfer/sass,jaroot32/sass,OrenBochman/sass,Galactix/sass,JuanitoFatas/sass,nazar-pc/haml,haml/haml