This is not a final PR

There were some issue with Redcarpet gem while parsing inline html tags which crapped up the structure of the generated HTML content from the rake task. And, there are some markdown formatting issues in some of the readmes in the main Sinatra repos — I've sent a PR there. Those changes are added to this PR.  

I will merge these changes with the 1.4.x branch and squashing my previous commits to the same once this gets approved.

The syntax highlighting is done by Coderay gem that is packed in Kramdown.

@rkh: Let me know if I should remove the ToC removal code and use yours instead. As I pointed out earlier, I went the Nokogiri path to ensure support to other language READMEs in case ToCs are added to them in the future.