The user selects two locations, and the correct map file is drawn, showing
those two locations. Exactly as for assignment 3.

Then your program finds the shortest route between the two locations, and
draws it on the map.

Also the program should print helpful driving instructions. The exact format
is up to you, but it should be something along these lines:

  Go North on I-95 for 52 miles to near Pompano Beach
  West on FL-814 for 6 miles to near Margate
  North on FL-817 for 2 miles to Coral Springs, your destination.

Note that long roads are split up into small segments. We don't want to see

  North on I-95 for 1.5 miles
  North on I-95 for 2.1 miles
  North on I-95 for 1.3 miles
  North on I-95 for 0.7 miles
  North on I-95 for 1.0 miles

Wait until there is a change, and just output (for that example)

  North on I-95 for 6.6 miles