Downgrade grunt-shell, fixes conflicts
Downgrade grunt-shell, fixes conflicts

grunt-shell@0.6.3 causes some issues such as :
https://github.com/sindresorhus/grunt-shell/issues/56

blubrackets/codebox,code-box/codebox,smallbal/codebox,lcamilo15/codebox,ahmadassaf/Codebox,rajthilakmca/codebox,quietdog/codebox,indykish/codebox,etopian/codebox,rodrigues-daniel/codebox,fly19890211/codebox,ronoaldo/codebox,kustomzone/codebox,smallbal/codebox,quietdog/codebox,rajthilakmca/codebox,CodeboxIDE/codebox,LogeshEswar/codebox,fly19890211/codebox,Ckai1991/codebox,blubrackets/codebox,CodeboxIDE/codebox,LogeshEswar/codebox,rodrigues-daniel/codebox,code-box/codebox,nobutakaoshiro/codebox,kustomzone/codebox,etopian/codebox,nobutakaoshiro/codebox,ahmadassaf/Codebox,listepo/codebox,indykish/codebox,Ckai1991/codebox,listepo/codebox,ronoaldo/codebox,lcamilo15/codebox