Fix doxygen warnings

doc/mainpage.dox.in

@@ -271,6 +271,11 @@ in different ways. This will motivate us to continue the efforts.
   \defgroup group_core_munkres Munkres Assignment Algorithm
   Munkres Assignment Algorithm.
 */
+/*!
+  \ingroup group_core_tools
+  \defgroup group_core_cpu_features CPU features
+  CPU features.
+*/
 
 /*******************************************
  * Module io

modules/core/include/visp3/core/vpMutex.h

@@ -121,42 +121,42 @@ class vp_deprecated vpMutex
 
     \class vpScopedLock
 
-    \ingroup group_core_mutex
+    \ingroup group_core_threading
 
     \brief Class that allows protection by mutex.
 
     The following example shows how to use this class to protect a portion of
     code from concurrent access. The scope of the mutex lock/unlock is determined
     by the constructor/destructor.
 
-\code
- #include <visp3/core/vpMutex.h>
+    \code
+    #include <visp3/core/vpMutex.h>
 
-int main()
-{
-  vpMutex mutex;
+    int main()
+    {
+      vpMutex mutex;
 
-  {
-    vpMutex::vpScopedLock lock(mutex);
-    // shared var to protect
-  }
-}
+      {
+        vpMutex::vpScopedLock lock(mutex);
+        // shared var to protect
+      }
+    }
     \endcode
 
     Without using vpScopedLock, the previous example would become:
     \code
-#include <visp3/core/vpMutex.h>
+    #include <visp3/core/vpMutex.h>
 
-int main()
-{
-  vpMutex mutex;
+    int main()
+    {
+      vpMutex mutex;
 
-  {
-    mutex.lock();
-    // shared var to protect
-    mutex.unlock()
-  }
-}
+      {
+        mutex.lock();
+        // shared var to protect
+        mutex.unlock()
+      }
+    }
     \endcode
 
     More examples are provided in \ref tutorial-multi-threading.

modules/core/src/tools/geometry/vpPlane.cpp

@@ -36,7 +36,6 @@
 /*!
   \file vpPlane.cpp
   \brief definition of the vpPlane class member functions
-  \ingroup libtools
 */
 
 #include <visp3/core/vpPlane.h>
@@ -60,7 +59,7 @@ vpPlane &vpPlane::operator=(const vpPlane &p)
 /*!
   Basic constructor that set the plane parameters A, B, C, D to zero.
 */
-vpPlane::vpPlane() : A(0), B(0), C(0), D(0) {}
+vpPlane::vpPlane() : A(0), B(0), C(0), D(0) { }
 
 /*!
   Plane constructor from A, B, C, D parameters.
@@ -72,7 +71,7 @@ vpPlane::vpPlane() : A(0), B(0), C(0), D(0) {}
   \param a, b, c, d : Parameters of the plane.
 
 */
-vpPlane::vpPlane(double a, double b, double c, double d) : A(a), B(b), C(c), D(d) {}
+vpPlane::vpPlane(double a, double b, double c, double d) : A(a), B(b), C(c), D(d) { }
 
 /*!
   Copy constructor.
@@ -177,8 +176,9 @@ void vpPlane::init(const vpPoint &P, const vpPoint &Q, const vpPoint &R, vpPlane
     b[0] = P.get_X() - R.get_X();
     b[1] = P.get_Y() - R.get_Y();
     b[2] = P.get_Z() - R.get_Z();
-  } else {
-    // Calculate vector corresponding to PQ
+  }
+  else {
+ // Calculate vector corresponding to PQ
     a[0] = P.get_oX() - Q.get_oX();
     a[1] = P.get_oY() - Q.get_oY();
     a[2] = P.get_oZ() - Q.get_oZ();
@@ -317,7 +317,8 @@ double vpPlane::rayIntersection(const vpPoint &M0, const vpPoint &M1, vpColVecto
     H[0] = M0.get_X() + k * R[0];
     H[1] = M0.get_Y() + k * R[1];
     H[2] = M0.get_Z() + k * R[2];
-  } else {
+  }
+  else {
     scal = getA() * M1.get_X() + getB() * M1.get_Y() + getC() * M1.get_Z();
     // if (scal != 0)
     if (std::fabs(scal) > std::numeric_limits<double>::epsilon())

modules/core/src/tools/geometry/vpRect.cpp

@@ -37,7 +37,6 @@
 /*!
   \file vpRect.cpp
   \brief Defines a rectangle in the plane.
-  \ingroup libtools
 */
 
 #include <visp3/core/vpDebug.h>
@@ -48,7 +47,7 @@
   and \e width and \e height set to 1.
 */
 
-vpRect::vpRect() : left(0), top(0), width(0), height(0) {}
+vpRect::vpRect() : left(0), top(0), width(0), height(0) { }
 
 /*!
   Constructs a rectangle with the \e top, \e left corner and \e width
@@ -59,7 +58,7 @@ vpRect::vpRect() : left(0), top(0), width(0), height(0) {}
   \param w : rectangle width.
   \param h : rectangle height.
 */
-vpRect::vpRect(double l, double t, double w, double h) : left(l), top(t), width(w), height(h) {}
+vpRect::vpRect(double l, double t, double w, double h) : left(l), top(t), width(w), height(h) { }
 
 /*!
   Constructs a rectangle with \e topLeft the top-left corner location
@@ -71,8 +70,7 @@ vpRect::vpRect(double l, double t, double w, double h) : left(l), top(t), width(
 */
 vpRect::vpRect(const vpImagePoint &topLeft, double w, double h)
   : left(topLeft.get_u()), top(topLeft.get_v()), width(w), height(h)
-{
-}
+{ }
 
 /*!
   Constructs a rectangle with \e topLeft the top-left corner location

modules/robot/include/visp3/robot/vpSimulatorCamera.h

@@ -48,7 +48,7 @@
 /*!
  * \class vpSimulatorCamera
  *
- * \ingroup group_robot_simu_Camera
+ * \ingroup group_robot_simu_camera
  *
  * \brief Class that defines the simplest robot: a free flying camera.
  *