Please describe the problem:
Setting a OptionEntry's long name to G_OPTION_REMAINING no longer works in glibmm 2.16.0. It used to work fine in older releases. I'm not sure if this is the appropriate way to parse out the remaining command line arguments, if there is another way it should be documented and/or put in the options example.

Steps to reproduce:
1. Build and run test case below
2.
/* g++ -o test-opts `pkg-config --libs --cflags gtkmm-2.4` main.cc */

#include <glibmm.h>
#include <iostream>

class Options : public Glib::OptionGroup
{
public:
	Options();

	int dummy;
	std::vector<Glib::ustring> args;
};

Options::Options()
: Glib::OptionGroup("Test", "Command line options"), dummy(0)
{
	Glib::OptionEntry e_dummy;
	e_dummy.set_long_name("dummy");
	e_dummy.set_short_name('d');
	add_entry(e_dummy, dummy);

	Glib::OptionEntry e_remaining;
	e_remaining.set_long_name(G_OPTION_REMAINING);
	add_entry(e_remaining, args);
}

int main(int argc, char *argv[])
{
	Options options;

	Glib::OptionContext context("[FILE...]");
	context.set_main_group(options);

	try
	{
		context.parse(argc, argv);
	}
	catch (const Glib::OptionError& e)
	{
		std::cerr << e.what() << std::endl;
		return 1;
	}

	std::cout << "dummy: " << options.dummy << std::endl;
	std::cout << "parsed remaining args: ";
	for (Glib::OptionGroup::vecustrings::const_iterator iter = options.args.begin(); iter != options.args.end(); ++iter)
	{
		std::cout << *iter << ", ";
	}
	std::cout << std::endl;

	std::cout << "left in argv: ";
	for (int i = 1; i < argc; i++)
	{
		std::cout << argv[i] << ", ";
	}
	std::cout << std::endl;
}


Actual results:
./test-opts random -d 1 remaining args
dummy: 1
parsed remaining args: 
left in argv: random, remaining, args, 

Expected results:
./test-opts random -d 1 remaining args
dummy: 1
parsed remaining args: random, remaining, args, 
left in argv: 

Does this happen every time?
yes

Other information:
It seems to be specific to glibmm, I tried a similar test case in plain c/glib and the remaining args were parsed properly.