pre-screening to figure out the required settings

[alexg9010]

including a pre-screening step into the pipeline, where a small subset of the reads is processed with the bismark pipeline in non-directional mode to figure out the required settings

with this we could initially figure out whether we have a directional or non-directional library at hand. running the complete data in directional vs non-directional mode cuts the required alignments with Bismark by half, so is definitely worth checking before.

also we might detect early issues with polyG at the end of the reads due to sequencing on illuminas NextSeq machine.