Url update and Html special char convertion

Was looking for a hackernews feed reader and found you project. Just what I needed! Thanks for it!

I'm sending you these two commits and three small changes.

1. Just a small fix on the url. Hackernews is only accessible through HTTPS now.
2. Added two html special char convertion (/ and ') which were naturally in numerical code.
3. Changed the piping of seds to using -e to chain the commands. It's a bit faster that way.

I tested these changes on OS X. I think maybe you should try it on a GNU sed just to make sure.

Hope you like it!