Bad sequence inputs like DManpa1-4-OH don't throw a good error

[gitoliver]

Bad inputs don't throw a good error:

Example: DManpa1-4-OH

GLYCAM-Web/website#286

[gitoliver]

Check the logs from running this through the gmml2 carb builder to see where it's not catching the lack of a residue.
A correct sequence would be DManpa1-OH.
This is not urgent: garbage in.