Feature request: allow stdin/stdout with maskfasta

[bartgrantham]

I have a feature request: allow the maskfastacommand to take - as the filename for both -fi and -fo to allow piping fasta files through maskfasta. So something like this would be possible

zcat unmasked.fa.gz | bedtools maskfasta -bed mask.bed -fi - -fo - | gzip -c - > masked.fa.gz

Even better if it did this by default:

zcat unmasked.fa.gz | bedtools maskfasta -bed mask.bed | gzip -c - > masked.fa.gz

Thank you for the consideration!