Better error handling

[faroit]

we assume that the sample rates of the signals and the length of the references and estimates are the same. However often, users might not be aware of this and it would make sense to warn them already in the local test submission.

we have:

music-demixing-challenge-starter-kit/evaluator/music_demixing.py

Lines 95 to 96 in 4cd3be8

	reference, _ = sf.read(reference_file)
	estimate, _ = sf.read(estimate_file)

I think we should add

• a check of the sample rates (the second argument _) these should the same (int(reference_rate) == int(estimate_rate))
• a check of the shape of the files (reference.shape == estimate.shape)