* doc improvements in Cwise and PartialRedux:

- 33 new snippets
  - unfuck doxygen output in Cwise (issues with function macros)
  - more see-also links from outside, making Cwise more discoverable
* rename matrixNorm() to operatorNorm(). There are many matrix norms
  (the L2 is another one) but only one is called the operator norm.
  Risk of confusion with keyword operator is not too scary after all.

Eigen/src/Array/PartialRedux.h

@@ -139,10 +139,13 @@ struct ei_member_redux {
   * \param ExpressionType the type of the object on which to do partial reductions
   * \param Direction indicates the direction of the redux (Vertical or Horizontal)
   *
-  * This class represents an expression with additional partial reduction features.
+  * This class represents a pseudo expression with partial reduction features.
   * It is the return type of MatrixBase::colwise() and MatrixBase::rowwise()
   * and most of the time this is the only way it is used.
   *
+  * Example: \include MatrixBase_colwise.cpp
+  * Output: \verbinclude MatrixBase_colwise.out
+  *
   * \sa MatrixBase::colwise(), MatrixBase::rowwise(), class PartialReduxExpr
   */
 template<typename ExpressionType, int Direction> class PartialRedux
@@ -180,30 +183,50 @@ template<typename ExpressionType, int Direction> class PartialRedux
 
     /** \returns a row (or column) vector expression of the smallest coefficient
       * of each column (or row) of the referenced expression.
+      *
+      * Example: \include PartialRedux_minCoeff.cpp
+      * Output: \verbinclude PartialRedux_minCoeff.out
+      *      
       * \sa MatrixBase::minCoeff() */
     const typename ReturnType<ei_member_minCoeff>::Type minCoeff() const
     { return _expression(); }
 
     /** \returns a row (or column) vector expression of the largest coefficient
       * of each column (or row) of the referenced expression.
+      *
+      * Example: \include PartialRedux_maxCoeff.cpp
+      * Output: \verbinclude PartialRedux_maxCoeff.out
+      *      
       * \sa MatrixBase::maxCoeff() */
     const typename ReturnType<ei_member_maxCoeff>::Type maxCoeff() const
     { return _expression(); }
 
     /** \returns a row (or column) vector expression of the squared norm
       * of each column (or row) of the referenced expression.
+      *
+      * Example: \include PartialRedux_norm2.cpp
+      * Output: \verbinclude PartialRedux_norm2.out
+      *      
       * \sa MatrixBase::norm2() */
     const typename ReturnType<ei_member_norm2>::Type norm2() const
     { return _expression(); }
 
     /** \returns a row (or column) vector expression of the norm
       * of each column (or row) of the referenced expression.
+      *
+      * Example: \include PartialRedux_norm.cpp
+      * Output: \verbinclude PartialRedux_norm.out
+      *      
       * \sa MatrixBase::norm() */
     const typename ReturnType<ei_member_norm>::Type norm() const
     { return _expression(); }
 
     /** \returns a row (or column) vector expression of the sum
       * of each column (or row) of the referenced expression.
+      *
+      * Example: \include PartialRedux_sum.cpp
+      * Output: \verbinclude PartialRedux_sum.out
+      *      
       * \sa MatrixBase::sum() */
     const typename ReturnType<ei_member_sum>::Type sum() const
     { return _expression(); }
@@ -216,7 +239,10 @@ template<typename ExpressionType, int Direction> class PartialRedux
   *
   * \returns a PartialRedux wrapper of *this providing additional partial reduction operations
   *
-  * \sa class PartialRedux
+  * Example: \include MatrixBase_colwise.cpp
+  * Output: \verbinclude MatrixBase_colwise.out
+  *
+  * \sa rowwise(), class PartialRedux
   */
 template<typename Derived>
 inline const PartialRedux<Derived,Vertical>
@@ -229,7 +255,10 @@ MatrixBase<Derived>::colwise() const
   *
   * \returns a PartialRedux wrapper of *this providing additional partial reduction operations
   *
-  * \sa class PartialRedux
+  * Example: \include MatrixBase_rowwise.cpp
+  * Output: \verbinclude MatrixBase_rowwise.out
+  *
+  * \sa colwise(), class PartialRedux
   */
 template<typename Derived>
 inline const PartialRedux<Derived,Horizontal>