Bar graph, phase 1

*The bar graph is done, except for the window title. The method
arguments were changed to make Prompt do the data extraction from the
hashmap in order to prevent some awful code redundancy.
*You can select the the first four data types and "area" or "population"
to get the option to display the data graphically.
*The segmented graph method, for the last two data types, is not
implemented, nor is the map method for latitude and longitude.