extra features and changes

Hi,

I really like the sheer simplicity of susi *but*  added some extra features that I needed to get the website I was working on built.
I'm not sure if these now push susi way past the simplicity you wanted for it? so please let me know if that's the case and instead I'll properly fork and give my variant a new name to distinguish it from susi and drop this PR.

Also my changes are very rough to get something working, so I'm planning to get things cleaned up some more, so if you are interested in taking the extra features I'll get the code cleaned up and submit a new PR.

thanks again for a very nice piece of code!