Edit notebooks so that dataframes only show first five entries

[dosumis]

e.g.

neurons_in_DA3 = vc.get_instances("'neuron' that 'overlaps' some 'antennal lobe glomerulus DA3'", summary=True)
neurons_in_DA3

=>

neurons_in_DA3 = vc.get_instances("'neuron' that 'overlaps' some 'antennal lobe glomerulus DA3'", summary=True)
neurons_in_DA3[0:5]

Without this, the docs in the tutorial are very hard to read.

IIRC, these limits were not needed on the original notebooks for the tutorials because these automatically limited, or => scrollable subwindows.