Implement parameters D

[pgleeson]

Being worked on here: https://github.com/openworm/CElegansNeuroML/tree/params_d

• Test & merge to master
• Incorporate in this figure
• Need to load in axonal/dendritic connection locations generated from RegenerateConnectome.py (possibly just load in the nml2 generated by this script...) and use these in generated network file.