[GEV TREND TEST] add gev trend test two parameters (for Location and scale parameters). IMPORTANT: Now the definition of test sign correspond to the sign of the strength (i.e. the increase with respect to some quantile)

[GEV TREND TEST] rename and refactor the code for one parameter gev trend test (to prepare the introduction of tests with two parameters)

[PAPER1] modify the strength criterion for the hypercube (use the 0.98 quantile and its evolution in 10 years)