Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().
Remove those uses, as they are no longer required.
https://bugzilla.gnome.org/show_bug.cgi?id=686161
Several flaws were pointed out by Shaun McCance. We were
leaking handled arguments, and we were mishandling the last
argument, and we were actually skipping arguments too.
https://bugzilla.gnome.org/show_bug.cgi?id=647031