* 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.

doc/snippets/MatrixBase_rowwise.cpp

@@ -0,0 +1,5 @@
+Matrix3d m = Matrix3d::Random();
+cout << "Here is the matrix m:" << endl << m << endl;
+cout << "Here is the sum of each row:" << endl << m.rowwise().sum() << endl;
+cout << "Here is the maximum absolute value of each row:"
+     << endl << m.cwise().abs().rowwise().maxCoeff() << endl;