Clustal Omega truncates headers to 127 characters

[mooreryan]

Clustal will still run but it will truncate headers to 127 characters.

I think the simplest way to handle it is to warn the user that they have headers longer than those accepted by clustal.

In the long run, a solution could be to have pasv write out short IDs for the files that go into the alignment then write out the real ID in the signatures file.