Add new Substituents

[ReneRanzinger]

Expansion of the list of substituent has been requested by multiple parties. We will use this ticket to collect the new substituent. The current list can be found in the GlycoCT defintion on page 16.

[ReneRanzinger]

One common modification for cell studies is to replace NAc with NAz.
e.g.; GalNAz

[kiyoko]

@ReneRanzinger The link to the current list is not valid...

[ReneRanzinger]

@kiyoko Fixed it. Some of them even exist as chemical drawing.