ONNX Export?

[DrDub]

I'd like to further contribute to FANN.

I'm thinking in the lines of an ONNX export.

(ONNX import, as requested by #125 might need too many primitives currently missing but with, although merging the ReLU PR in #147 get us closer to it.)

Would you be interested in merging such feature?

[bukka]

Hi, yes for sure. I would be happy to review it and get it merged. If this gets implemented, I think it would be also time for a new version of the library after many years...