ARRaycastManager support added

Important update!

It turned out that ARPlaneManager.Raycast() and ARPointCloudManager.Raycast() work in coordinate space  of ARSessionOrigin. It means if your ARSessionOrigin is not located at default position (zero position, zero rotation and 1,1,1 scale) using these methods will produce wrong results. You can transform your ray to ARSessionOrigin local coordinates and back, but there is much simpler solution.

In this update I added ARRaycastManager support. This means you don't have to use ARPlaneManager.Raycast() and ARPointCloudManager.Raycast() anymore. From now on you can just use ARRaycastManager.Raycast(). To enable it to work in Editor, please add  ARPlaneManager and/or ARPointCloudManager to ARSessionOrigin.