[ONNX compliance] Adhere to automated ONNX scoreboard backend

[mciprian13]

I don`t know if you know this but in the ONNX project there is an automated backend to test the degree of compliance with the ONNX standard. Check this:
ONNX Scoreboard
ONNX Scoreboard Backend
I think Glow should be plugged-in as well. This should ease the testing of the ONNX features (there is huge list of unit tests) and pave the way to higher compliance with ONNX.
Tell me what you think.