Be able to handle https subscriptions

By setting use_ssl=true on the Net::HTTP object.

I tried to follow `ssweeny@status.ssweeny.net` and got an EOFError. His hub url is `'https://status.ssweeny.net/main/push/hub'`, and [this SO question](https://stackoverflow.com/questions/5244887/eoferror-end-of-file-reached-issue-with-nethttp?rq=1) helped me figure out the problem.