Port NextFlow examples to Seamless, once this can be cleanly done

[sjdv1982]

See the examples tab on https://www.nextflow.io/ . Interesting examples: Blast, RNASeq, Machine Learning (other examples are either too simple or too messy).

First, need to finish #183 .

The Blast example makes use of the NextFlow channel splitFasta, this must be added as an includable (#119). Scatter syntax (#143) would be nice for this, too.

The NextFlow channel "fromFilePairs" should probably be added as a command line runner feature . (RNAseq example)

The machine learning example contains a lot of if statements, this requires stdlib.select to be brushed up (#181).