Codes related to GASP: a lazy grounding based interpreter for ASP

Launch SICStus Prolog, compile the GASP interpreter.
Set (if needed) the working directory. Then launch the goal
:- go('testxxx.lp'). for all (printed) solutions,
:- go('testxxx.lp',no). for all (non printed) solutions,
:- go('testxxx.lp',_,write). for the first (printed)solution.
:- go('testxxx.lp',_,no). for the first (non printed)solution.
tests3-6 needs to comment/uncomment some lines if tested with an ASP solver different from GASP.