[BioRuby] Codeml parser

[Pjotr Prins]

I have updated the writeup at

  http://bioruby.open-bio.org/wiki/BIORUBY_PAML

have a look at my PAML branch. The (old) unit tests pass.

  http://github.com/pjotrp/bioruby/tree/PAML

I have to add the positive selection sites, to complete it.

Pj.