PL2 computes and plots the Outdegree-Exponent Power-Law in FFF99.  This power-law states that the
frequency, fd, of an outdegree, d, is proportional to the the outdegree to the power of a constant,
O. (Requires Gnuplot to plot and Ghostview to view plot)

Contributors:   Michalis Faloutsos, Petros Faloutsos, Christos Faloutsos
Reference:      [FFF99] On Power-Law Relationships of the Internet Topology, in ACM Sigcomm 1999.   
Implemented by: BRITE Development Team
