From: Vijay Baharani <vibahara@umd.edu>

For a weighted directed graph, the first X lines of the file contain the name 
of every vertex.  A blank line follows.  Next are sets of lines.  In each set, 
the first line is a vertex name.  All following lines up until a blank line 
are in pairs: the first line is the name of the vertex being pointed toward, 
and the second line is the weight of that directional edge.  I am choosing 
to exclude having the number of vertices or edges stated in the text file.  
The end of the file is given by when readLine() returns null.

Example:
F
R
I
J

I
J
13.0
F
5.0

F
R
0.0
J
2.0

J
R
7.0

R
I
8.0

An undirected unweighted graph is almost exactly the same - I simply deleted 
the weights from the above file.

Example:
F
R
I
J

I
J
F

F
R
J

J
R

R
I