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_f.F90

@@ -217,6 +217,7 @@ contains
                 write(stdout, '(a)') error_msg
                 ! Maybe also abort if the output is necesssary or handle this
                 ! some other way.
+                stop
             endif
 #endif
             call jall%balance()
@@ -235,6 +236,7 @@ contains
             write(stdout, '(a)') error_msg
             ! Maybe also abort if the output is necesssary or handle this
             ! some other way.
+            stop
         endif
 #endif