footerのデザインいじってみた closes #389 closes #283

# before
![d7ee285892cbb425129f5581d31d3239](https://cloud.githubusercontent.com/assets/1044064/4781872/b4a5bace-5cc5-11e4-9b33-04551be2c198.png)


# after
![fc1648f25932ba643c987130d500138f](https://cloud.githubusercontent.com/assets/1044064/4781871/a1b9bc8a-5cc5-11e4-8b38-e4cc64d9d594.png)