[Biopython] HMMER / Pfam support

[Kyle]

I would like to submit my hmmer branch for merge into the main BioPython
tree, targeting inclusion in 1.57.
This branch adds support for HMMER3 file parsing and some Pfam related file
work. It's adapted from the PfamScan perl code found at
ftp://ftp.sanger.ac.uk/pub/rdf/PfamScanBeta/
The code can be found at https://github.com/kellrott/biopython/tree/hmmer

Kyle