fix: a typo in CORS header name (#712)
fix: a typo in CORS header name (#712)

`Access-Control-Allow-Method` was missing `s` :)

![2018-11-24--15-19-22](https://user-images.githubusercontent.com/157609/48969265-c45c9900-effc-11e8-9bc2-9405db96f312.png)

ipfs/station,ipfs/station