Test and fix "pickleability" of Binary objects
which has been recently broken while some cubes rely on this (eg fastimport).
Do some licensing/pep8 cleanup along the way.
Closes #13385274
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/html/index.html
Files: /usr/share/doc/cubicweb-documentation/html/*