plugins: compositor: add support to set parent window id as window property

Having the ID of the parent window enables us to do window stacking in the shell easily.
Initially the client has to set the parent ID correctly and the shell is then responsible
to update it when the visual parent changes.

Signed-off-by: Simon Busch <morphis@gravedo.de>
plugins: shell: notifications: always log notification debug messages

We already handle qDebug output correctly depending on the log level configured for the
daemon so we don't have to disable everything at compile time.

Signed-off-by: Simon Busch <morphis@gravedo.de>
Merge pull request #90 from webOS-ports/parent-window-id

Parent window