The new clingo-4 does not have an inbuilt incremental solving mode anymore.
This example shows how this mode can be simulated via scripting.  For
convenience, the lua main function in iclingo-lua.lp has been embedded into
clingo and can be loaded with the #include statements (see example
iclingo-lua.lp).

Example calls:
    clingo iclingo-int.lp example.lp
    clingo iclingo-lua.lp example.lp
    clingo iclingo-py.lp example.lp
