Notify about application destruction

Notify about application destruction

Currently agl-compositor notifies about application ids which can be
activated/deactivated, as well as the application state. However, when
an application is destroyed this information is not communicated to desktop
making it out of sync with the actual list of available applications.

To overcome this limitation extend the protocol and the logic to notify
about application destruction on surface remove.

Signed-off-by: Walter Lozano <walter.lozano@collabora.com>
Change-Id: Ib766cf3f3fbd10f55b85212480dc4717ab1bec22