Function slerp

slerp<T>(a, b, t, dst?): T
Spherically linear interpolate between two quaternions
Type Parameters
- T extends BaseArgType = number[]
Parameters
- a: BaseArgType
  starting value
- b: BaseArgType
  ending value
- t: number
  value where 0 = a and 1 = b
- Optional dst: T
  quaternion to hold result. If not passed in a new one is created.
Returns T
A quaternion that is the result of a * b