Ensure read_free is called for WebP buffer data
Correct VipsArea ref count in PNG buffer output
Merge pull request #168 from lovell/png-save-buffer-unref-area-7.40

Correct VipsArea ref count in PNG buffer output
Merge pull request #167 from lovell/webp-read-buffer-leak-7.40

Ensure Read struct is freed when reading WebP image data from a buffer
update ChangeLog
Merge branch '7.40'