The fold change filter can apply symmetrically (both up and down) or only
in one direction, depending on the cardinality operator (one of the
choices offered by cardinalNumericField: "<=",
">=", ">= or <= -", "<= and >= -") and the sign of
the limit. This picks the matching subset of rows from the lines
data frame built in buildMaLines, where rows 1-2 are the
fold-down threshold and rows 3-4 the fold-up threshold.
