Added RNA18S5 and RNA28S5 to maskfile.

	grep -P "gene_type \"pseudogene\"" $GENCODEGTF | grep -P RNA18S5  >>
$OUTDIR/mask.gff
	grep -P "gene_type \"pseudogene\"" $GENCODEGTF | grep -P RNA28S5  >>
$OUTDIR/mask.gff