SceneRayCaster does not recognize camera within hierarchy deeper than 1

[griestopf]

In https://github.com/FUSEEProjectTeam/Fusee/blob/master/src/Engine/Core/SceneRayCaster.cs#L222 only the innermost transformation at the node containing the camera component is taken into accont. If the camera node is nested in a hierarchy of transformations all parent transformations are ignored leading to erroneous picking results.