Add option to assign ASV to multiple species with DADA2

[andand]

Description of feature

Corresponding to setting allowMultiple = TRUE in assignSpecies or addSpecies.

[erikrikarddaniel]

Would make sense. I can foresee some parsing problems of the resulting output file, but nothing that can't be dealt with. A test case would hence be good.

[erikrikarddaniel]

I just realized you can probably do this right away by creating a nextflow.config file with the following content:

process {
    withName: DADA2_ADDSPECIES {
        ext.args = "allowMultiple = TRUE, n = 1e5"
    }
}

If this breaks the output or not, I'm not sure, but if you try please report what happened.

[d4straub]

Added that option to dev, will be in release 2.8.0.