write direct SWC import for b3d

[schlegelp]

That way we don't have to initialise CatmaidNeurons

[jefferis]

b3d?

[schlegelp]

pymaid.b3d is the module that contains functions to interface with Blender. Currently SWC imports into Blender have to first load the data as a CatmaidNeuron which creates overhead. Would be nice to have a (optional) shortcut.

[schlegelp]

Idea: subclass CatmaidNeuron into a MinimalNeuron without the upfront generation of a graph representation, etc?

[jefferis]

My neuron base class is simpler than catmaidneuron. I have previously regretted not having a vertex3d type class representing anything that has 3D points.