* LU decomposition, supporting all rectangular matrices, with full

pivoting for better numerical stability. For now the only application is
determinant.
* New determinant unit-test.
* Disable most of Swap.h for now as it makes LU fail (mysterious).
Anyway Swap needs a big overhaul as proposed on IRC.
* Remnants of old class Inverse removed.
* Some warnings fixed.

Eigen/src/Core/MatrixBase.h

@@ -526,6 +526,7 @@ template<typename Derived> class MatrixBase
 
 /////////// LU module ///////////
 
+    const LU<EvalType> lu() const;
     const EvalType inverse() const;
     void computeInverse(EvalType *result) const;
     Scalar determinant() const;