Quaternion: pass vector parameters by reference

src/Quaternion.h

@@ -21,7 +21,7 @@ class Quaternion {
 	Quaternion();
 	Quaternion(T w, T x, T y, T z);
 	// from angle and axis
-	Quaternion(T ang, vector3<T> axis)
+	Quaternion(T ang, const vector3<T> &axis)
 	{
 		const T halfAng = ang * T(0.5);
 		const T sinHalfAng = sin(halfAng);
@@ -33,7 +33,7 @@ class Quaternion {
 	// Create quaternion from normalized direction vectors.
 	// This creates a quaternion representing the rotation from the second
 	// unit direction vector to the first unit direction vector.
-	Quaternion(vector3<T> to, vector3<T> from)
+	Quaternion(const vector3<T> &to, const vector3<T> &from)
 	{
 		// Use half-angle trig identities to skip invoking trig functions
 		T cosAng = to.Dot(from);