Add ItemRole

Add a role to get the QQuickItem associated with the preflet.

Issue: #13
Reference iconName role from model

Feels a lot better now.

Issue: #13
Push and pop views

Push the preflet item when the icon is clicked and pop the current view
when the "Overview" action is triggered.

Issue: #13
Don't use old VStandardDirs

Use QStandardPaths from Qt.
Fix wallpapers path

Add missing slash.
Add license text and copyright notice

Forgot to add it before.
Background preflet initial version

Long live Background preflet.

Issue: #13