A Quaternion describes a rotation in 3D space. The Quaternion is mathematically defined as Q = xi + yj + z*k + w, where (i,j,k) are imaginary basis vectors. (x,y,z) can be seen as a vector related to the axis of rotation, while the real multiplier, w, is related to the amount of rotation.
@param x Multiplier of the imaginary basis vector i.
@param y Multiplier of the imaginary basis vector j.
@param z Multiplier of the imaginary basis vector k.
@param w Multiplier of the real part.
@see http://en.wikipedia.org/wiki/Quaternion
