Adds flag to give back SSH url instead of HTTP

FYI
@supremebeing7 If the method `parse_response_from` grows past the current two arguments `post` and `wants_ssh`... 

We probably should look at merging the `posts` and `attributes` hash after the HTTP POST. This will make it cleaner.

Something along the lines of LINE 37:
`Githubrepo.parse_response_from( post.merge(attributes))`