Ignore comments column and drop Bio.Alphabet

[rpetit3]

The MLST profile for Candida glabrata has a column named comments which is not in the ignore list. This PR adds it to the ignore list, as well as drops Bio.Alphabet which has been removed in latest Biopython versions.

https://pubmlst.org/bigsdb?db=pubmlst_cglabrata_seqdef&page=downloadProfiles&scheme_id=1

ST  FKS LEU2    NMT1    TRP1    UGP1    URA3    comments
1   7   1   1   6   4   4   
2   1   2   2   1   1   1   
3   5   7   8   7   3   6   
4   7   3   9   8   1   5   
5   5   7   8   1   3   6   
6   2   5   7   5   1   2   
7   3   4   4   3   3   4   
8   1   2   2   1   2   1   

[puethe]

Thanks!