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 incmode-lua.lp has been embedded into
clingo and can be loaded with an #include statement (see example
incmode-lua.lp).

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