Build in memory, as a structure of interconnected nodes, the graph described by these files:
   http://rabbit.eng.miami.edu/class/een318/intersections.txt
   http://rabbit.eng.miami.edu/class/een318/connections.txt
   http://rabbit.eng.miami.edu/class/een318/geog.txt

Your program should then ask the user to specify a starting location, and allow him/her/it
to interactively navigate through the map.


example

Location to start: 19999

Location 19999, 0.66 miles from Shelby, NC
roads leading away:
  1: NC-18, 1.005 miles to location 19977
  2: US-74, 2.521 miles to location 19991
  3: US-74, 3.749 miles to location 20006
  4: NC-18, 7.565 miles to location 20159
take which road? 3

Location 20006, 1.85 miles from Light Oak, NC
roads leading away:
  1: bus-US-74, 3.812 miles to location 19977
  2: US-74, 3.749 miles to location 19999
  3: US-74, 4.805 miles to location 20022
take which road? 1

Location 19977, ... etc.