NavigationWidget: Do not leak the factorymodel

Change-Id: Ic5c5dfd2ef9b3daab1f3e04375930fc991bff0e8
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
CMake: Initialize useNinja to false

Change-Id: I0fbc22efa6aacae2c1921c56ca0f41d4576bfc00
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
NavigationWidget: Pass reference into function

Change-Id: Ic2e90daee4036d1e513db16d35dd72f4e7a667c7
Reviewed-by: Daniel Teske <daniel.teske@digia.com>