Links to data in recipe interface

[borkurdotnet]

Currently we have no trace from the subjects/attributes in the interface to the original data source. We should add this.

E.g. if you are looking at a traffic count attribute you should be able to get more information by being directed to http://www.dft.gov.uk/traffic-counts/

[lorenaqendro]

Update: print the original link at the end of the export or at some other point during the run.