* add Regression module, from eigen1, improved, with doc and unit-test.

* fix .normalized() so that Random().normalized() works; since the return
type became complicated to write down i just let it return an actual
vector, perhaps not optimal.
* add Sparse/CMakeLists.txt. I suppose that it was intentional that it
didn't have CMakeLists, but in <=2.0 releases I'll just manually remove
Sparse.

Eigen/src/Core/MatrixBase.h

@@ -330,7 +330,7 @@ template<typename Derived> class MatrixBase
     Scalar dot(const MatrixBase<OtherDerived>& other) const;
     RealScalar norm2() const;
     RealScalar norm()  const;
-    const ScalarQuotient1ReturnType normalized() const;
+    const EvalType normalized() const;
     void normalize();
 
     Transpose<Derived> transpose();