Test that adding a non-callable to the Middleware stack fails
Test that adding a non-callable to the Middleware stack fails

designermonkey/Slim,foxyantho/Slim,JoeBengalen/Slim,Sam-Burns/Slim,AndrewCarterUK/Slim,mnapoli/Slim,feryardiant/slim,akrabat/Slim,dopesong/Slim,iinux/Slim,opengeek/Slim,jaapverloop/Slim,iinux/Slim,somjit2514/basic,juliangut/Slim,iinux/Slim,slimphp/Slim,samsonasik/Slim,RealSelf/Slim