Draw all sugar classes

glycans.xml needs to be extended! The list to use can be found here: https://www.ncbi.nlm.nih.gov/glycans/snfg.html

Presently only these classes are drawn:

• Hexose
• HexNAc
• Hexosamine
• Hexuronate
• Deoxyhexose

These needs to be added:

• DeoxyhexNAc
• Di-deoxyhexose
• Pentose
• Deoxynonulosonate
• Di-deoxynonulosonate
• Unkwnown
• Assigned