Add PyhsicsRaycastMethod to Viverig/controller/LaserPointer/Caster prefab

[csyhping]

Hi, according to the developer guide, the ViveRig prefab should be the combination of ViveCameraRig, VivePointers, ViveCurvePointers, and ViveColliders. The functionality should be the same but I notice that there isn't a PyhsicsRaycastMethod with ViveRig controller caster, this may cause trouble like dragging when using ViveRig. Just a kind reminder, maybe you could consider unifying these prefabs to avoid confusion in the next release :D. Hope this helpful to anyone who has the same puzzle with ViveRig.