clients: support ivi-application.xml for clients/simple-shm.c

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>

remove NULL entry in listener
clients: support ivi-application.xml for clients/simple-egl.c

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>

remove NULL entry in listener
clients: support ivi-application.xml for clients/window.c

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>

remove NULL entry in listener
Reference implementation of input panel for ivi-shell.

- introduces ivi-shell/input-panel-ivi.c

The basement of this code is from input-panel.c of desktop shell.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>