Use markdown for changelog

Right now our changelog is plain text file. There are at least two cases where html-version of changelog would be nice: 1. forum posts for new version 2. release notes for Sparkle updater. It’s really not a best idea to mantain two versions. So what about using makrdown syntax in changelog? It’s very simple and still readable as plain text but can be easily to nice html.

The forum needs bbcode (or plain text) and sparkle needs html, so it’s not unifiable anyway. Or, putting it another way, plain text is the only way to unify it (sacrificing niceness).