wayland-info: Add a cmdline option for interface
Currently, wayland-info will query the wl_display and print information about all the interfaces available.
In some cases however, information about just one specific interface is required.
This adds a command line option --interface (or -i for short) which prints the information only for the given interface.
Signed-off-by: Olivier Fourdan ofourdan@redhat.com Closes: #7 (closed)