Update configuration.haml

That ain't YAML. This is YAML.
Add Hound logo to home page

* Add Hound SVGs to home page
* Move line on homepage to the left
* Remove old hound image

https://trello.com/c/U2GJGKlo
Merge pull request #286 from bhardin/patch-1

Update configuration.haml
Clean up Commenter and CommentingPolicy specs

* Remove specs testing logic currently tested in `CommentingPolicy`
  specs from `Commenter`
* Don't stub unused and nonexistent methods in `CommentingPolicy` specs