MoReWeb v0.6.7

IV grading: also grade on measured value of leakage current at -20 degrees (with the same criteria than at +17). This will affect grading of modules that have both a higher leakage current at -20 than at +17 and a leakage current at -20 larger than 10 uA. (Not seen any so far, but one module would almost fulfill these criteria)