#14 FMUModelExchange::integrate() function ignores fmiStatus codes

[Michael Spiegel]

In case fmiGetDerivatives(...) returns an error, both default integrators (from Boost and Sundials) ignore it. Resulting from the error handling flaw, it was observed that integration was not sucessfully done because no results were returned and that the whole test system crashed because indirect integrator warning messages from Sundials overflooded some buffers. See SundialsStepper::f(...) in IntegratorStepper.cpp for an example where the status codes are ignored.

[Michael Spiegel]

Branch issue-14-integrator-error-handling now contains some test facilites and a test case which triggers the flaw.