Update readme for users running Storybook with npm 2
Update readme for users running Storybook with npm 2

Tried to fix the module structure for npm v2; but seems that babel api changes are incompatible with the old module structure,  so I just added instructions for fixing the issue for other npm 2 users
Entropy03/jianwei,LikeJasper/mantra-plus,mantrajs/mantra-sample-blog-app,mantrajs/meteor-mantra-kickstarter,markoshust/mantra-sample-blog-app,hacksong2016/angel,wmzhai/mantra-demo