Delete datasets

# Goodbye data-sets
![](http://37.media.tumblr.com/7303b6a1c5977ee216f8c0cf308f1aca/tumblr_n40x85mdGz1r5cijyo1_250.gif)![](http://37.media.tumblr.com/7303b6a1c5977ee216f8c0cf308f1aca/tumblr_n40x85mdGz1r5cijyo1_250.gif)

- Adds new method in write.api, with `DELETE` as method
- There are lots of places we're calling the token `create_bucket_token` or `dev-create-endpoint-token` or `CREATE_COLLECTION_ENDPOINT_TOKEN` and I'm using that for deleting as well, but it should probably change in a separate pull request.