Small example using the Z3 ML bindings.

To build the example execute
   make examples
in the build directory.

This will create ml_example and ml_example.byte in the build directory, which
can be run in the build directory by calling 
LD_LIBRARY_PATH=. ./ml_example
or
LD_LIBRARY_PATH=. ./ml_example.byte
for the byte-code version.

If Z3 was installed into the ocamlfind package repository (see
src/api/ml/README), then we can also compile this example as follows:  

ocamlfind ocamlc -o ml_example.byte -thread -package z3 -linkpkg ml_example.ml
or
ocamlfind ocamlopt -o ml_example -thread -package z3 -linkpkg ml_example.ml

Note that the resulting binaries depend on the shared z3 library
(libz3.dll/.so/.dylb), which needs to be in the PATH (Windows), LD_LIBRARY_PATH
(Linux), or DYLD_LIBRARY_PATH (macOS).
