GDDB: Graphical Datalog Debugger
Author: Jade Koskela <jtkoskela@ucdavis.edu>
http://github.com/jkoskela/gddb
Undergraduate Research Supervised by Dr. Bertram Ludaescher
Spring 2012

This program will render the model of a datalog database using Graphviz.
It provides tracing functionality, as well as interactive editing of styles.
For more information, See the report gddb.pdf.

Input:
  -Datalog rules
  -Facts
  -Style sheet - optional

Usage:
  gddb rules facts styles

Files:
  -gddb         : Main script.
  -parse_dlv.py : Parses datalog rules, creates auxiliary rules for input into dlv.
  -graphdlv.py  : Module for setting styles and rendering output.
  -gddb.py      : Command line interpreter for drawing datalog model and tracing.

Dependencies:
  -pydot
  -graphviz
  -ply   
  -cairo 
  -dlv

Note:
All styling is applied to predicates. Each predicate has it's own subgraph. It's attributes are then divided into graph, edges, and nodes sets.