Put more info on raycast callbacks

[ghost]

So, here is a scenario:
You have a rigid body that uses a compound shape.
You perform a raycast and hit the rigid body.

But you wish to know which child of the compound shape was hit, but the callbacks don't have that information, the best you can get is the rigid body that was hit.

During the callback processing, there are functions that take a LocalRayResult, like addSingleResult, which contains m_localShapeInfo, giving more information about the hit, such as m_triangleIndex, which can be used to obtain the child shape.

It would be very useful to have that bit of information without having to sub-class ray cast callbacks, like I did over here https://gitgud.io/stephenlynx/SpaceLynx/blob/master/src/CustomRayCast.cpp