We no longer use centiMorgan in GeneNetwork

From the email threads:

> ���
> Sorry, we now generally do not use centimorgans. Chr 19 is 57 cM
> using markers that exclude telomeres in most crosses.
> ���

and

> ���
> I know that cM is a bit more variable because it's not a direct measurement, ���
> ���

The uploader will store any provided physical location values (in megabasepairs) in the

• Geno table

specifically in the `Mb` field of that table.