Documentation updated explaining the initialization strings, and the …

…special characters of Unicode they use. A fix in the documentation of dimension.dox has been done too

docs/dox/units/dimension.dox

@@ -1,5 +1,5 @@
 /** \class scifir::dimension
-* \brief Class that represents dimensions of the SI system of units. Each prefix sizes 6 bytes, 1 byte for the dimension type, 1 byte for the prefix, 1 byte for the position (which can be the NUMERATOR or the DENOMINATOR), and 3 bytes for the custom dimension (in case it's used one).
+* \brief Class that represents dimensions of the SI system of units. Each dimension sizes 6 bytes, 1 byte for the dimension type, 1 byte for the prefix, 1 byte for the position (which can be the NUMERATOR or the DENOMINATOR), and 3 bytes for the custom dimension (in case it's used one).
 
 * \enum scifir::dimension::position
 * \brief Represents the position of the dimension, which can be at the numerator or at the denominator. The value NO_POSITION is used when there's no position specified.

docs/dox/units/scalar_unit.dox

@@ -1,5 +1,5 @@
 /** \class scifir::scalar_unit
-* \brief Class that allows to create scalar units, which are cmoposed of a value (as a float) and dimensions. The dimensions can be of any number, and be basic dimensions and/or abbreviations of dimensions.
+* \brief Class that allows to create scalar units, which are composed of a value (as a float) and dimensions. The dimensions can be of any number, and be basic dimensions and/or abbreviations of dimensions. **Initialization string** example: "1 N".
 
 * scalar_unit is a class that allows to have a scalar unit, which is composed of a value and one or more dimensions. All dimensions of the SI system of units are supported, and also all of its abbreviations. The abbreviations can be converted to its derived dimensions, too. scalar_unit classes have operators with all numeric types, and have operators with themselves. They can be displayed by its dimensions, its derived dimensions, or any custom combination of dimensions. When they change dimensions, like, for example, from meters to kilometers, their numeric value is changed accordingly.
 * POSSIBLE FEATURES

docs/dox/units/vector_unit_2d.dox

@@ -1,5 +1,5 @@
 /** \class scifir::vector_unit_2d
-* \brief Class that creates a vector unit in 2D. The vector is in **polar coordinates** with a value and dimensions of the scalar_unit, and an angle theta for his direction.
+* \brief Class that creates a vector unit in 2D. The vector is in **polar coordinates** with a value and dimensions of the scalar_unit, and an angle theta for his direction. **Initialization string** example: "1 N 20θ". 'θ' is the Unicode Character **U+03B8**.
 
 * \fn vector_unit_2d::vector_unit_2d()
 * \brief Default constructor. The value is set to 0, the dimensions are empty and theta is 0.

docs/dox/units/vector_unit_3d.dox

@@ -1,5 +1,5 @@
 /** \class scifir::vector_unit_3d
-* \brief Class that creates a vector unit in 3D. The vector is in **spherical coordinates** with a value and dimensions of the scalar_unit, and an angle theta and another angle phi for his direction.
+* \brief Class that creates a vector unit in 3D. The vector is in **spherical coordinates** with a value and dimensions of the scalar_unit, and an angle theta and another angle phi for his direction. **Initialization string** example: "1 N 20θ 30Φ". 'θ' is the Unicode Character **U+03B8**. 'Φ' is the Unicode Character **U+03A6**.
 
 * \fn vector_unit_3d::vector_unit_3d()
 * \brief Default constructor. The value is set to 0, the dimensions are empty and theta and phi are 0.

docs/dox/units/vector_unit_nd.dox

@@ -1,5 +1,5 @@
 /** \class scifir::vector_unit_nd
-* \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.
+* \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. **Initialization string** example: "1 N 20° 30° 40°". '°' is the Unicode Character **U+00B0**.
 
 * \fn vector_unit_nd::vector_unit_nd()
 * \brief Default constructor. The value is 0, the dimensions are empty and the angles are empty.