||This class contains definitions used in Parsing and Editing of numbers,
and the default representation of the NaN (null) value.
||Trigonometric and a few other functions used in the astronomical context.
||The astronomical time may be expressed in (Modified) Julian Days,
Julian Years or Besselian years.
||Class for 'nice' edition of numbers.
||This class interprets text and is able to convert to numbers,
or find a symbol in a list of symbols.
||Testing the Unit class.
||Class able to deal with scientific units and make the appropriate