fixed bug in sffinfo when ~ was used in the sff filename. fixed issue in shhh.flows...

fixed bug in sffinfo when ~ was used in the sff filename.  fixed issue in shhh.flows, it was producing an output file called *.flow.fasta instead of *.fasta. Also when using outputdir with the file option, it put the shhh.fasta and shhh.names files in the wrong folder.  changed format of rarefaction.single output with groups to look more like the phylo.diversity command.