Initial code review for knowledge sharing

This application is already deployed at uds.cslab.esss.lu.se, but I think it is good if someone besides me takes a look at how it works. There are many things that can be improved, for example code duplication or style. But I don't expect too much specific feedback in this review. It is more for knowledge sharing at this time. Comments are welcome, however. Please allow me to do the actual merge if you don't mind. I would like to experiment with the options.