allow limiting the amount of repos to display

by setting github_repo_count to someething that's not 0, you can limit
the amount of repositories to render

.themes/classic/source/_includes/asides/github.html

@@ -13,7 +13,12 @@
             var s = document.getElementsByTagName('script')[0];
             s.parentNode.insertBefore(jxhr, s);
         }
-        github.showRepos('{{site.github_user}}', '#gh_repos');
+
+        github.showRepos({
+            user: '{{site.github_user}}',
+            count: {{site.github_repo_count}},
+            target: '#gh_repos'
+        });
     });
   </script>
   <script src="{{ root_url }}/javascripts/github.js" type="text/javascript"> </script>