Implementation of solver for tight ASP programs using completion.
Added some tests for ASP.
Deleted useless folder.
Fixed bug on gringo input.
Merge remote-tracking branch 'origin/master' into asp

Conflicts:
	src/Solver.h
Added new test file.
Fixed bug on the exit code.
Merge branch 'master' into asp
Implemented class PostPropagator.
Implemented unfounded sets check.
Added test cases.
Fixed a memory leak.
Removed wrong assert in solver.
Variable elimination is performed also for non-tight programs. (Variable in cyclic components are frozen)
Added statistics for non-tight programs.
Fixed bug on post propagators learning.
Added tests.
Remove input builders.
Tab to space.
Start to revise reading of gringo input.
Remove GUS.
Remove InputFacade.
Remove iterations list-style.
Restore satelite.
Split tests in tight and nontight.
Fix a few bug with the input.