Fix some doxygen errors and warnings.

Eigen/Sparse

@@ -1,15 +1,15 @@
 #ifndef EIGEN_SPARSE_MODULE_H
 #define EIGEN_SPARSE_MODULE_H
 
-/** defgroup Sparse_modules Sparse modules
+/** \defgroup Sparse_Module Sparse meta-module
   *
   * Meta-module including all related modules:
-  * - SparseCore
-  * - OrderingMethods
-  * - SparseCholesky
-  * - SparseLU
-  * - SparseQR
-  * - IterativeLinearSolvers
+  * - \ref SparseCore_Module
+  * - \ref OrderingMethods_Module
+  * - \ref SparseCholesky_Module
+  * - \ref SparseLU_Module
+  * - \ref SparseQR_Module
+  * - \ref IterativeLinearSolvers_Module
   *
   * \code
   * #include <Eigen/Sparse>

doc/A05_PortingFrom2To3.dox

@@ -281,7 +281,7 @@ result = Vector4f::MapAligned(some_aligned_array);
 
 \section StdContainers STL Containers
 
-In Eigen2, #include<Eigen/StdVector> tweaked std::vector to automatically align elements. The problem was that that was quite invasive. In Eigen3, we only override standard behavior if you use Eigen::aligned_allocator<T> as your allocator type. So for example, if you use std::vector<Matrix4f>, you need to do the following change (note that aligned_allocator is under namespace Eigen):
+In Eigen2, <tt>#include<Eigen/StdVector></tt> tweaked std::vector to automatically align elements. The problem was that that was quite invasive. In Eigen3, we only override standard behavior if you use Eigen::aligned_allocator<T> as your allocator type. So for example, if you use std::vector<Matrix4f>, you need to do the following change (note that aligned_allocator is under namespace Eigen):
 
 <table class="manual">
 <tr><th>Eigen 2</th><th>Eigen 3</th></tr>

doc/Manual.dox

@@ -135,6 +135,8 @@ namespace Eigen {
     \ingroup Sparse_Reference */
 /** \addtogroup IterativeLinearSolvers_Module
     \ingroup Sparse_Reference */
+/** \addtogroup Sparse_Module
+    \ingroup Sparse_Reference */
 /** \addtogroup Support_modules
     \ingroup Sparse_Reference */    
 

doc/TutorialSparse.dox

@@ -2,7 +2,7 @@ namespace Eigen {
 
 /** \eigenManualPage TutorialSparse Sparse matrix manipulations
 
-\eigeneigenAutoToc
+\eigenAutoToc
 
 Manipulating and solving sparse problems involves various modules which are summarized below:
 
@@ -14,7 +14,7 @@ Manipulating and solving sparse problems involves various modules which are summ
 <td>%Sparse LU factorization to solve general square sparse systems</td></tr>
 <tr><td>\link SparseQR_Module SparseQR \endlink</td><td>\code #include<Eigen/SparseQR>\endcode </td><td>%Sparse QR factorization for solving sparse linear least-squares problems</td></tr>
 <tr><td>\link IterativeLinearSolvers_Module IterativeLinearSolvers \endlink</td><td>\code#include <Eigen/IterativeLinearSolvers>\endcode</td><td>Iterative solvers to solve large general linear square problems (including self-adjoint positive definite problems)</td></tr>
-<tr><td>\link Sparse_modules Sparse \endlink</td><td>\code#include <Eigen/Sparse>\endcode</td><td>Includes all the above modules</td></tr>
+<tr><td>\link Sparse_Module Sparse \endlink</td><td>\code#include <Eigen/Sparse>\endcode</td><td>Includes all the above modules</td></tr>
 </table>
 
 \section TutorialSparseIntro Sparse matrix format

doc/snippets/Cwise_asin.cpp

@@ -0,0 +1,2 @@
+Array3d v(0, sqrt(2.)/2, 1);
+cout << v.asin() << endl;