axon from dendrite discussion

[arnaudon]

I found the PR which made sanitize crash: #52
See BlueBrain/NeuroM#977 (comment)

[eleftherioszisis]

The homogeneity check is required for our circuits, therefore the check cannot be removed. However, it could become optional with its respective flag:

def sanitize(input_neuron, output_path, allow_inhomogeneous_trees=False)