catch all exceptions in all tutorials and examples

tutorials/tutorial3.cpp

@@ -93,6 +93,7 @@
 /// \snippet tutorial3.cpp main
 /// \internal [main]
 int main ()
+try
 {
     /// \internal [main]
     /// \endinternal
@@ -316,6 +317,10 @@ int main ()
         Opm::writeVtkData(grid, dm, vtkfile);
     }
 }
+catch (const std::exception &e) {
+    std::cerr << "Program threw an exception: " << e.what() << "\n";
+    throw;
+}
 /// \internal [write output]
 /// \endinternal