1.5.1 Sphere obstacles small update

Adds the information of the gamma distributed spheres into it's correspondent file.

1.5 (2021) developing merge

Several changes regarding the obstacle handling.

• Automatic signal separation,

• Automatic compartmental particles initialization

• Memory Optimization for large and multiple PLY models.

• PLY list integrations.

• Spherical obstacles integrations

1.43 stable version.

01-08-2020 Jonathan Rafael

• Several changes in the handling of mesh collisions including, active particle tracking for volume computation, and sentinel's changes to final position tracking. Minor spelling and comments corrections.
• [tag] compute_voume added. This option is now available for the Monte-Carlo estimation of the volume of closed oriented meshes.
• walker_ini_pos (intra/extra) now works automatically for closed oriented meshes.
• <spawn_area> </spawn_area> is now supported for the intra/extra particle's intialization.

1.42 Frontiers in Neuroinformatics release.

Release 1.42 including all features depicted in: https://www.frontiersin.org/articles/10.3389/fninf.2020.00008/full