major version change: refactored _run_vep() to select consequence, variation, sift & polyphen values from specified gene/feature combination (multiple entries for same exon_id from vep, with varying sift, polyphen, consequence & variation vals taken into hashref meant last one wins); added cds and protein annotation vals; vep data row skipped & warning issued if ENSG0000* gene id not present in transcripts db