Blender 2.78c is shipped with a version of the io_blend_utils module that
doesn't have a `pythonpath()` function yet, and that's bundled with an
older version of BAM. To work around this, we ship BAM as wheel, and detect
whether this version is needed to run.
As an added bonus, Blender 2.78c can now also use the file exclude filter
for Flamenco. The `bam_supports_exclude_option()` function is thus no
longer necessary.
Usually this will be because someone just wants to use the wheel, but
during development this can be caused by other issues, and shouldn't
be silenced.
Making the blender_cloud.pillar and blender_cloud.cache modules usable
without Blender required some moving of the code, from __init__.py to
blender.py.
CacheControl requires the lockfile package, which increases the number
of bundled wheel files to 3. Those are now managed by
blender_cloud.wheels.load_wheels(). The wheels are only loaded if the
Python installation doesn't yet contain the required packages. This allows
development with virtualenv-installed packages, debugging in the IDE, etc.
