Solve a big issue with data alignment and dynamic allocation:

* add a WithAlignedOperatorNew class with overloaded operator new
* make Matrix (and Quaternion, Transform, Hyperplane, etc.) use it
  if needed such that "*(new Vector4) = xpr" does not failed anymore.
* Please: make sure your classes having fixed size Eigen's vector
  or matrice attributes inherit WithAlignedOperatorNew
* add a ei_new_allocator STL memory allocator to use with STL containers.
  This allocator really calls operator new on your types (unlike GCC's
  new_allocator). Example:
  std::vector<Vector4f> data(10);
  will segfault if the vectorization is enabled, instead use:
  std::vector<Vector4f,ei_new_allocator<Vector4f> > data(10);
NOTE: you only have to worry if you deal with fixed-size matrix types
with "sizeof(matrix_type)%16==0"...

Eigen/src/Geometry/Quaternion.h

@@ -59,6 +59,9 @@ template<typename _Scalar> struct ei_traits<Quaternion<_Scalar> >
 
 template<typename _Scalar>
 class Quaternion : public RotationBase<Quaternion<_Scalar>,3>
+  #ifdef EIGEN_VECTORIZE
+  , public ei_with_aligned_operator_new<_Scalar,4>
+  #endif
 {
   typedef RotationBase<Quaternion<_Scalar>,3> Base;
   typedef Matrix<_Scalar, 4, 1> Coefficients;