blog-detailの下部分調整 closed #351

・コメントのwidthをarticleの幅と合わせた
・starの位置も調整


before
![988e439a3494689bdbf06a531244c325](https://cloud.githubusercontent.com/assets/1044064/4754176/43bbe730-5abc-11e4-8d12-bbbb1937941f.png)

after
![5d86f3059773b1a23c3ad7f03b4b426f](https://cloud.githubusercontent.com/assets/1044064/4754143/134928a6-5abc-11e4-819b-0f96d431d5ff.png)