adding support for HTML tags in the node title

I recently added HTML Title to my Drupal system.
I also use the Disqus module.
I noticed that HTML tags were being translated to html special characters when a node title that contained tags was being submitted to Disqus and subsequently displayed in my 'recent comments' block (see screenshot for a better explanation).

Here is a proposed patch that seems to fix this issue (all I added was the strip_tags functions inside the check_plain function).