Added a SVD module:

- the decompostion code has been adfapted from JAMA
 - handles non square matrices of size MxN with M>=N
 - does not work for complex matrices
 - includes a solver where the parts corresponding to zero singular values are set to zero

Eigen/src/Core/util/ForwardDeclarations.h

@@ -98,6 +98,7 @@ void ei_cache_friendly_product(
 
 template<typename MatrixType> class LU;
 template<typename MatrixType> class QR;
+template<typename MatrixType> class SVD;
 template<typename MatrixType> class Cholesky;
 template<typename MatrixType> class CholeskyWithoutSquareRoot;