fastq-writing bug-fixes and cleanups

- unify code-paths for single-/paired-fastq writing

  also use recalibrated qualities

- shorten `-validation` argument to adam2fastq

- add first/second-in-pair to adam2fastq projection

  these are necessary for outputting “/1”/“/2”!

- optional extra pair-checking to adam2fastq

- add extra check to fastq test suite

- whitespaces