* Minor coding-style clean up

   * Minor coding-style clean up
   * Replace the ContentEntry and its derived classes (BinEntry and ValEntry)
     by the DataEntry. This unique entry considers all datas like binary datas.
     Some methods are added to interpret - at fly - the binary datas.
     Due to this important change, some methods of the DocEntrySet, concerning
     the BinEntry and ValEntry classes, are erased ; and new methods for the
     DataEntry class are created.
     Some methods to set the ValEntry or the BinEntry are renamed to
     correspond to the new DataEntry, like for example :
      - SetValEntry -> SetEntryString
      - SetBinEntry -> SetEntryBinArea
     This change will remove all useless creation of the string when working
     directly on values.
   -- BeNours