test_advanced_image_processing: Added test for extract_f0 from advanced_image_processing. This fixes #99.
advanced_image_processing: Added doctest for normalize_data. This fixes #100.
advanced_image_processing: Added doctests for get_neuron_dtype from advanced_image_processing. This fixes #103.
advanced_image_processing: Added doctests for get_empty_neuron from advanced_image_processing. This fixes #104.
advanced_image_processing: Added doctests for get_one_neuron from advanced_image_processing. This fixes #105.
advanced_image_processing: Added the function extract_neurons, which will extract neurons from an image given a stack of masks.