CHANGES: 27/04/2014: - create first code to read the main database in a WDB file and convert then as spreadsheet 04/02/2014: - create first code to read the main spreadsheet in a WKS file 28/12/2013: - change code to depend on librevenge -------- begin of version 0.3 --------- -------- end of version 0.2 --------- 25/05/2013: - end of improving code to read WPS files