Adding support to read three-dimensional somata and build them accurately.

Received some SWC morphology file from @orena1. The file contains multiple soma contours at different depths-of-field. These contours are being handled for the moment as basal dendrites. We therefore must integrate a utility to identify the presence of 3d somata contours and reconstruct them accurately with metaball algorithm only. I think that the SoftBody simulation might not be that accurate.