To use the checker, execute it in a terminal console with two parameters, the exit code 
from the solver and the path to the problem instance, and giving, in standard input, a 
witness as a set of facts on a single line. The checker will assess whether this 
represents a connected still live or not.

Requires clingo (tested with version 3.0.4). http://potassco.sourceforge.net

For example, to test a correct and an incorrect solution, use the following commands:

	./checker.sh 10 ../example/instance.asp < rightSolution.txt
	./checker.sh 10 ../example/instance.asp < wrongSolution.txt

In case of correct solution, the checker returns OK and the solution cost on stdout, and 
exits with code 0.
