Specify lower limit to number of cross-validation segments

[eschen42]

Currently, a high number of cross-validation segments causes some comparisons to be suppressed. For example, with three replicates of three treatments, the current minimum of 7 suppresses pair-wise contrasts because one cannot use 7 cross-validation segments with six samples.

Add a parameter min_crossval_i (with a default value of 7) to specify this, and use its value in lieu of 7 in lines 603, 677, 756, and 809 of w4mcorcov_calc.R, all of which currently are

, x_crossval_i  = min(7, length(chosen_samples))

[eschen42]

Fixed in commit 5fd9687 for release v0.98.18