Print help text when callin gie without arguments

Previously gie would return "Nothing to do" when called without
arguments. With this change the help text is returned instead.

src/gie.c

@@ -247,7 +247,7 @@ int main (int argc, char **argv) {
     if (0==o)
         return 0;
 
-    if (opt_given (o, "h")) {
+    if (opt_given (o, "h") || argc==1) {
         printf (usage, o->progname);
         return 0;
     }