updated gist_tag.rb to use <div>s to get around RDiscount's foolishness

plugins/gist_tag.rb

@@ -34,8 +34,8 @@ module Jekyll
     def html_output_for(script_url, code)
       code = CGI.escapeHTML code
       <<-HTML
-<script src='#{script_url}'></script>
+<div><script src='#{script_url}'></script>
-<noscript><pre><code>#{code}</code></pre></noscript>
+<noscript><pre><code>#{code}</code></pre></noscript></div>
       HTML
     end