Added support for Markdown style links. Fixes issue #5.

This pull request adds support for Markdown style links in the titles.

I understand using a javascript Markdown parser plugin would also fix this, but it would be a bigger change, while this is a pretty small regex match. And besides, links seem to be the most useful feature from Markdown to use in the titles, so a full parser would be overkill (no need for lists, headers, paragraphs, code blocks...).