#62 Reference file auto download

[Swami Kevala]

Allow the user to overwrite his existing reference file with one from a specified URL. Possible to set up so that every time the user opens the application, the application will attempt to check if the online reference.xml has been updated more recently than the local reference.xml. If it has been, then the user will be prompted to allow the application to automatically download the online reference.xml file to the database.