Add M1 model in FastCodeML
Would be good to have M1 model (and M0 model?) in FastCodeml.
This way we could estimate parameters (kappa and branch lengths) directly in FastCodeml before running the branch-site model, in the same run.
Currently this is what is done in Selectome in different steps: M1 (or M0) model is run in codeml, then kappa and branch length estimations are parsed and used for branch-site model (estimated kappa as starting point, branch lengths as fixed lengths).