Add data to output: sign flag, sign specific rank

[johan]

Add a column to the output containing a sign flag (+ or -) indicating if the average M value is larger than zero (up regulated) or smaller than zero (down regulated).

Add a column with a sign specific rank, i.e., from rank 1 and down for upregulated (1, 2, 3, 4, and so on) reporters and rank 1 and down for downregulated reporters (-1, -2, -3, -4, and so on).