updated multi_Scan.r added 3 code files

added functions thres.U localmax.D calc.U.region in multi_Scan.r
added thresholding_and_testing.r for finding the significant regions and
saving the U or D statistics for testing
added getcutoff_func.r to find the cutoff for U.Sum and U.WSum
added simu_cutoff.r to simulate the cutoff for D.Sum, D.WSum, and D.HC