Helper function for multiplication of two quaternions. Concatenation of two rotations R1 followed by R2
product_Q4(q1, q2, normalize = FALSE)
object of class "quaternion"
two objects of class "quaternion"
. first rotation R1 expressed by q1 followed by second rotation R2 expressed by q2
logical. Whether a quaternion normalization should be applied (TRUE) or not (FALSE, the default).