Add more figures from paper to NEURON script

[pgleeson]

Update scripts here: https://github.com/OpenSourceBrain/SolinasEtAl-GolgiCell/tree/master/NEURON with options for generating figures. e.g.

• Fig 2A - No pacemaking?
• Fig 3A
• Fig 4A
• Fig 4B, middle (using python script to generate FI curve, e.g. see here) - fix text - traces don't match figure
• Fig 5A - different freq in 50% Ih
• Fig 5 B
• Figure 6 A&B - Change colours to match figure if possible
• Figure 7 A&B
• Figure 9 A, B & C - Change colours to match figure if possible

[pgleeson]

@RokasSt is working on these here: https://github.com/RokasSt/SolinasEtAl-GolgiCell/tree/master/NEURON