Get rid of old-style classes

[ylep]

Old-style classes are classes that do not inherit from object. In Python 3 every class is new-style, because classes implicitly inherit from object.

In order to get a consistent behaviour across Python 2 and Python 3, all old-style classes should be changed to inherit from object. Old-style classes can be detected by the hacking flake8 plugin (flake8 --select=H238 .).

Projects that need to be checked for old-style classes:

• [x] casa-distro
• [x] brainvisa-cmake
• [x] soma-base
• [x] soma-workflow
• [x] capsul
• [x] axon
• [x] aims-free
• [x] aims-gpl
• [x] anatomist-free
• [x] anatomist-gpl
• [x] morphologist
• [x] morphologist-ui
• [x] morpho-deepsulci
• [x] cortical_surface
• [x] brainrat
• [x] disco
• [x] constellation
• [x] nuclear-imaging-private
• [x] nuclear-imaging-gpl
• [x] highres-cortex
• [x] datamind
• [x] brainvisa-spm
• [x] data_storage_client
• [x] fmri
• [x] longitudinal_pipelines
• [x] snapbase