Fortran error tests

Fortran error tests should be added, as suggested in #13 (closed).

For this some things have to be reworked, additional error checking enabled (such as correct permissions for already existing VTK output directories), that we can use to test against.

example/ALL_Staggered.cpp

@@ -228,6 +228,7 @@ int main(int argc, char** argv)
 			jall->printVTKoutlines(CurrentStep);
 		} catch (ALL::FilesystemErrorException &e) {
 			std::cout << e.what() << std::endl;
+			std::exit(2);
 			// Maybe also treat this error in some way, e.g. whether the simulation
 			// should abort if no output could be written or not.
 		}