Display summary and description

As a new gem author, I was pretty puzzled by the contrast between:

* The specification docs, which say: "The description should be more detailed than the summary." ( http://guides.rubygems.org/specification-reference/#summary 
* The actual output on the site, which only shows the summary if both are present.

This patch takes into account the reality that many authors have been working around the current `show` logic by putting what should be in the description in the summary: it removes the 'summary' match from the 'description' output.

Thanks!