UI should default to using structural/3D info from cellParams (template) when not found in cells (instance)

[pgleeson]

Error found when importing JSON representation of networks.
The info on cell structure is present in the cell params entry as a template for all cells in that population, but each of the entries under net/cells/0 etc. normally has a repeat of this. It can be missing though (file):

I get an error when I load this in the UI. The UI should fall back to using the info in the cellParams template when it is missing in the instance

[Muhaddatha]

Please ignore my commit above from July 29th. I made a mistake with the issue number in the commit message. The commit is related to issue #347 and not #374.

[pgleeson]

I think this is fixed now with the nml related updates