Minor changes name of variable and messages
Changes in different flies of the name of variable Global.effort_preponderant to Global.envir_preponderant to be consistent with earlier modification in the wording of the associated question. Improvement of the content of model.txt and help files. Addition of new test files .CLI.
src/fr/ird/climprod/resources/help/PUEUNSTA.HLP → src/fr/ird/climprod/resources/help/UNSTABILCPUE.HLP