Allow no last space for gist number only in gist tag

Closes #1394
Merge branch 'master' of github.com:imathis/octopress

* 'master' of github.com:imathis/octopress:
  removing border from iframe in jsFiddle plugin
  * properly escaped site title and post/page title in the RSS feeds;
  * consistently convert page and post titles to titlecase if site.titlecase is true;