Descriptions of taxonomic classes

[TathagataChakraborti]

Is your feature request related to a problem? Please describe.

It's hard to tell what each taxonomic class does right now, there is no description attached to the nodes.

Describe the solution you'd like

1. Configuration entry to tell the compiler to look for descriptions.
2. Alternative rows of descriptions and labels in the master spreadsheet.

3. Descriptions go into the modals that open up when the node is clicked.

@sarathsreedharan