Quite a bit of progress on the Comments controller and views.
- Comments controller reverted to ApplicationController base class, since #create, #index and #new methods now implemented.
- Specs for controller #create, #index and #new, testing both success and failure for #create and #new.
- View specs for 'comments/index'  and 'comments/new' actions.

Trivially, added a free clip art "logo" image because I was sick and tired of looking at the 'broken-image' marker when firing up the app in the browser.

FIXME: Note that the view specs in particular could be DRYed up considerably.
Updated README.md to state that Version 1.0 DOES NOT require `show` or `delete` actions for the `Comment` controller.