Hrde app

This PR includes a number of improvements, new features and bug fixes to the application formally known as the hazard viewer. 
Please enclose all the buttons in a div with a specific, but generic id (like 'map-tools'). This is needed to calculate the correct map height by ```static/js/base_data_viewer_app.js``` which must be ```body - header - footer - map-tools```. Currently is calculated only ```body - header - footer```, so there's an offset of ~26px, but I cannot fix it in a good way because the enclosing div (and id) is missing.