v1.9.15
Remove trailing whitespace from test output.
Prefer fputs over fprintf where possible
Avoid using %zu or %zd with printf() and fprintf().
Use #include <foo.h> instead of #include "foo.h" in most cases.
Make most python tests pass with Python 3.4 Dictionary order is not stable in Python < 3.6 so we need to sort by key to have consistent results. The LogHandler output is also different on older Python versions. Also, don't stop running python tests after the first error.
plugins/python/regress: add a failing textcase about python plugins affect each other
plugins/python/regress: add test for callback error msg return
Adapt to changed formatting of a rejected result in Python 3.12