* added an in-place version of inverseProduct which

might be twice faster fot small fixed size matrix
* added a sparse triangular solver (sparse version
  of inverseProduct)
* various other improvements in the Sparse module

Eigen/src/Core/util/Constants.h

@@ -191,6 +191,11 @@ enum {
   Sparse  = SparseBit
 };
 
+enum {
+  ColMajor = 0,
+  RowMajor = RowMajorBit
+};
+
 const int FullyCoherentAccessPattern  = 0x1;
 const int InnerCoherentAccessPattern  = 0x2 | FullyCoherentAccessPattern;
 const int OuterCoherentAccessPattern  = 0x4 | InnerCoherentAccessPattern;