Provide AGL extension, wl_shell support for Wayland-IVI-Extension.
This components is merged in meta-agl/meta-ivi-common. Additionally, AGL
demo, Home screen, requires, wh_shell support as well. This patch enable
wl_shell_emulator to support wl_shell. This patch also provide README
how to enable this feature in weston.ini and try it out. In details,
please visit AGL wiki,
https://wiki.automotivelinux.org/agl-distro/demo-apps/home-screen
Change-Id: Ieff9ed030eedbdeab285c5e75e2f6dddb765352a
Signed-off-by: Nobuhiko Tanibata <ntanibata@jp.adit-jv.com>