This is basically a bugfix release that tries to take care of as many known issues as possible. Especially memory leaks have been hunted down this time and as a result a lot of the cython code was changed to be less likely to create circular references.

The second half of the work was making alpha handling less bad. It’s now possible to pass a second alpha clip to set_output() in scripts and vspipe will output it. Unfortunately y4m can’t be combined with alpha and no other output method currently preserves the alpha but at least some workflows with alpha should be a simpler now.

Breaking changes:

• IMWRI now requires Q16 or Q32 ImageMagick 7 with HDRI enabled
• The imwri namespace is now always imwri since a single version can handle all formats
• And basically everything else in IMWRI