modify custom/filterdifferentialtable to allow >=/<=

[suzannejin]

This modification allows setting ">=" or "<=" comparisons through ext.args

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[pinin4fjords]

The interface is a little confusing here. But in any case, you're effectively making the cardinality a required input here, which means it should go in through a channel.

I suggest we change the inputs from:

    tuple val(meta), path(input_file)
    val(logFC_column)
    val(FC_threshold)
    val(padj_column)
    val(padj_threshold)

To:

    tuple val(meta), path(input_file)
    val(logFC_column)
    val(FC_threshold)
    val(FC_cardinality)
    val(padj_column)
    val(padj_threshold)
    val(padj_cardinality)

(removing the args thing altogether)

OR, maybe we also want to bundle these like:

    tuple val(meta), path(input_file)
    tuple val(logFC_column), val(FC_threshold), val(FC_cardinality)
    tuple val(padj_column), val(padj_threshold), val(padj_cardinality)

There should then be a check for a valid cardinality ('-', '<', '>', '<=', or '>=').

[suzannejin]

@pinin4fjords Hello!! Thank you for the suggestions! Now the cardinal comparison operators are explicitly given as input :)

[pinin4fjords]

Looking good, thanks for addressing feedback