Classifications from NP Classifier should be one-to-many

[flange-ipb]

Hello,

I compared a bit the results from NP Classifier with what is shown in COCONUT and I think each of the three classification outcomes ("Pathway", "Super Class" and "Class") should cover many values instead of only one. If you work with NP Classifier's API or with its classify_structure function then you'll observe that the field values are always a list of strings.

Examples:

• Epothilone A:
  • COCONUT's CNP0198699.1 has one pathway ("Amino acids and Peptides")
  • NP Classifier's classification consists of two pathways ("Amino acids and Peptides" and "Polyketides") which also makes sense when you look at the biosynthesis.
• 6-Methyl-5-hepten-2-one:
  • COCONUT's CNP0330890.0
  • NP Classifier's classification

[vcnainala]

Addressed in #802.