Add cmake module for libuuid
Add UUID interface for object type
Added callback NULLing for other types
Add ws_object_uuid() stub
Add implementation of ws_object_uuid()
Add libuuid to build env
Add UUID callback for ws_wayland_obj type
Remove: ws_wayland_obj_get_id()
Fix: The cmp callback for the ws_wayland_obj can now use the uuid
Add uuid library to tests
Merge pull request #210 from matthiasbeyer/add-object_uuids

Add UUIDs in ws_object