ts/wf/cross [FIX][!!!][API]: make output file name last on command line

In order to be compatible with the previous version, the output file is again
defined to be last on the command line.

src/ts/wf/cross.cc

@@ -75,7 +75,7 @@ int main(int iargc, char* argv[])
   {
     CROSS_VERSION "\n"
     "usage: cross [-v] [-o] [-D] [-convolve] [--itype t] [--otype f]\n"
-    "             outfile file [f:F] [t:T] [file [f:F] [t:T] [...]]\n"
+    "             file [f:F] [t:T] [file [f:F] [t:T] [...]] outfile\n"
     "   or: cross --help|-h" "\n"
     "   or: cross --xhelp" "\n"
   };
@@ -90,12 +90,12 @@ int main(int iargc, char* argv[])
     "-itype t     file format for input files\n"
     "-otype t     file format for output files\n"
     "\n"
-    "outfile      output file" "\n"
     "file ...     input file(s)" "\n"
     "             t:T select traces T, where T may be any range\n"
     "                 specification like '3-4' or '5,6,7-12,20'\n"
     "             f:F specifies an input file format differing from\n"
     "                 the format selected by \"--itype\"\n"
+    "outfile      output file" "\n"
     "\n"
     "--xhelp      print details on supported I/O formats\n"
     "\n"
@@ -181,9 +181,12 @@ int main(int iargc, char* argv[])
   if (opt.verbose) { cout << CROSS_VERSION << endl; }
 
   TFXX_assert(cmdline.extra(), "missing input file!");
-  std::string outfile=cmdline.next();
-  TFXX_assert(cmdline.extra(), "missing output file!");
   tfxx::cmdline::Tparsed arguments=parse_cmdline(cmdline, cmdlinekeys);
+  TFXX_assert(arguments.size()>1, "missing output file!");
+  // extract output file name and remove from list
+  std::string outfile=arguments.back().name;
+  arguments.pop_back();
+
   if ((arguments.size()>1) && opt.verbose)
   {
     cout