Liferea code repo moved to github

I moved the source repo away from SourceForge away to GitHub. It is currently located here: https://github.com/lwindolf/liferea If in doubt always follow the "Code" link from the website to find the repo. Sorry, if this causes troubles for you. I'll contact all with current git write access directly to see how we can continue on github and who will be able to merge. Please keep contributing! I think with github this can actually become easier and more developers are familiar with its best practices.