brief command added to the class description inside the documentation…

… of vector_unit_nd.dox

docs/dox/units/vector_unit_nd.dox

@@ -1,5 +1,5 @@
 /** \class scifir::vector_unit_nd
-* Class that creates a vector in ND, which means a variable number of dimensions. A vector_unit_nd can change to be in 1D, in 2D or in 3D, but it cannot be in more than one dimension at the same time. The member-variables of vector_unit_nd are the value and the vector<dimension> of scalar_unit, and a vector<angle> angles. The number of angles is equal to the number of dimensions vector unit has - 1. In 1D vector_unit_nd doesn't has angles, in 2D vector_unit_nd is in **polar coordniates** an has 1 angle, and in 3D vector_unit_nd is in **spherical coordinates** an has 2 angles.
+* \brief Class that creates a vector in ND, which means a variable number of dimensions. A vector_unit_nd can change to be in 1D, in 2D or in 3D, but it cannot be in more than one dimension at the same time. The member-variables of vector_unit_nd are the value and the vector<dimension> of scalar_unit, and a vector<angle> angles. The number of angles is equal to the number of dimensions vector unit has - 1. In 1D vector_unit_nd doesn't has angles, in 2D vector_unit_nd is in **polar coordniates** an has 1 angle, and in 3D vector_unit_nd is in **spherical coordinates** an has 2 angles.
 
 * \fn vector_unit_nd::vector_unit_nd()
 * \brief Default constructor. The value is 0, the dimensions are empty and the angles are empty.