Check if solver and solver Java API versions match during build

[arg0n1s]

If there is a (major) version mismatch between the Solver implementation and the Solver Java API (e.g., GUROBI), the instantiation of the Solver will fail with a null pointer. Without background knowledge it is not clear why this happens, as no suitable error message is thrown that hints towards this version mismatch. In fact, such a message cannot be thrown since the JNI implementation of the GUROBI API does not check for errors and, thus, does not throw appropriate exceptions itself.

I suggest to check the version of the desired solver and the solver API provided by us during the build process. If the corresponding path variable is not set or references the wrong version, we will point this out.