Small example using the user-propagator.
To build the example execute
   make examples
in the build directory.

This command will create the executable user_propagator_example.
On Windows, you can just execute it.
On macOS and Linux, you must install z3 first using
   sudo make install
OR update LD_LIBRARY_PATH (Linux) or DYLD_LIBRARY_PATH (macOS) with the build directory. You need that to be able to find the Z3 shared library.
