Prevent multitoken options from eating tokens after '--' separator.

Thanks to Gevorg Voskanyan for the bug report and the testcase.


[SVN r52440]

libs/program_options

@@ -1 +1 @@
-Subproject commit ed4847e0a71eb267df61265172dd15ba3f684cf2
+Subproject commit 3c6401b19a6399d465909f0fb4dd8ca9b682e6f1