Fix the compositor's wayland versioning

We cannot just assume all clients implement the same version of the
various interfaces as the compositor does. Keep track of them, and
react accordingly when creating a resource or sending an event.

Change-Id: I9792433a14d49c5c4df0c892fc1349ce0dfb0d43
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>