Added basic isso commenting system integration
* [isso](http://posativ.org/isso/) is a Disqus like commenting system written in Python
** self-hosted i.e. no privacy implications
** lightweight and provides all the features I require for this blog
* I thought about implementing a commenting system in InputXSLT but sadly I just don't have the time to think of and implement a reasonable XSLT based solution
** maybe a simple REST service for pushing XML from the client into article-dependend comment directories can be implemented in the future
* added basic CSS styling for isso comments simmilar to how they currently look in the old Symphony CMS based blog