Add function to turn annotations into one hot encoding

[sprestrelski]

Turn weakly labeled files into a DataFrame using one hot encoding.

	Class 1	Class 2	Class 3	Class 4	Class 5	Class 6	Class 7
file1.wav	1	0	0	0	0	0	0
file2.wav	0	0	0	1	0	0	0
file3.wav	0	0	0	0	1	0	0

Example maybe here or here

[JacobGlennAyers]

I imagine that this would be for ease of use with a library such as PyTorch? I.E. it is useful when trying to use PyHa outputs as training data?

What would be the added value of having that implemented natively in PyHa compared to using the existing functionality in deep learning frameworks?