You must now include vips7 support explicitly with #include <vips/vips7compat.h> in your code just after including `vips.h`. The old vips7 names, such as `Rect`, were starting to cause problems with other packages like opencv.
Also update LGPLv2.1 license text from the copy currently on the GNU website.
the deprecated tiff saver used to use pixels/mm in resolution specification, rather than the user's suggested unit
