improved management of tables in SEXTANTE
addded new SEXTANTE python algorithms
cleaned SEXTANTE/SAGA algorithms
[sextante] Log file is now read backwards and limited to a fixed number of lines
[sextante]minor fixes and added new R script examples
[sextante] improved toolbox and modeler to better use classification by categories (easy mode)
[sextante] added tools to ease creating unit test for algorithms