Refactor command-line handling of GUI options.
Both GTK and Qt both use the same command-line options, so refactor
the parsing and (possibly) applying of those arguments to a single
location.
Ping-Bug: 12546
Change-Id: Ib31e576c509c5d3d21c33d3247640d9f9c68661b
Reviewed-on: https://code.wireshark.org/review/16006
Reviewed-by: Michael Mann <mmann78@netscape.net>
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>