Pass -msse2 when using gcc/clang.
Update INSTALL regarding PYTHON variable.
Make failed tests output the exit code.
Add LIBDIR to LD_LIBRARY_PATH when running the Cython tests.
Try to locate python3 before python.
Revert "Update INSTALL regarding PYTHON variable."

This reverts commit a5f556e89711ec5703e7dee29ac86c0605321230.
Fix mistake in documentation
Merge branch 'master' of https://github.com/vapoursynth/vapoursynth.git
Add -start and -end arguments to vspipe
Improve VS_ALIGNED_MALLOC macro, fix bad use in eedi3
Vinverse: stop leaking source frames
VSPipe: improve usage string formatting
VSHelper: Add VSMIN/VSMAX macros

Pretty much everything needs those anyway, so might as well have
them there instead of duplicating them all the time.
Add Tesseract-based OCR filter
Add plugin for morphological filters
Add OCR and Morpho to the plugin list
Apply firesledge's rgvs mode 20 fix
Fix tests
Fix typo in lachs0r's test fix, add test for old argument reordering
Fix argument rearranging