READLEN varaible used as MAX and MIN value

[bridlin]

Hello!
The READLEN variable defined in the config file is used by cutadapt --minimum-length option to filter shorter reads out and by DADA2 as Trunclen option to cut the reads at this length.
This is a problem when there are amplicons that are shorter than the sequencing length as this will introduce variation in the expected read length.

Thanks Bridlin