Merge pull request #62 from webOS-ports/morphis/work

Morphis/work
plugins: compositor: remove direct rendering calls as API was removed upstream

Signed-off-by: Simon Busch <morphis@gravedo.de>
Implement WindowModel component

The WindowModel makes it possible to access all currently with the compositor registered
windows through a QAbstractListModel implementation.

Signed-off-by: Simon Busch <morphis@gravedo.de>
Inject StatusBarServicesConnector as context property rather than as singleton type

Using a singleton type stopped working with qt 5.2 so we're using a context property
instead.

Signed-off-by: Simon Busch <morphis@gravedo.de>