Change patter matching for read tuples
Read tuples are recognized for the presence of '_1'/'_2' or 'R1'/'R2', resp.. This introduces ambiguity: '_1' and consorts can be anywhere in the string, even '__1.fastq' is imaginable, and if '' would start with '1' also '__2.fastq' might match - likewise '__3.fastq'.
Better: impose the sorting string to be prior-suffixes.