remove "throw" from c++ autogen tools

and output

spelling

fix vips7 py enable flag

note change in svgload header

try disabling operation cache for magickload

magickload can eat huge amounts of memory and disc, fon't keep it in the
operation cache

see https://github.com/jcupitt/libvips/issues/731

clearer usage notes for cli

see https://github.com/jcupitt/libvips/issues/725

fix webp upscale in thumbnail

we could try to use webp shrink on load to upscale, oops

see https://github.com/jcupitt/libvips/issues/710

oops, forgot something

Merge branch '8.5' into tweak-smartcrop-8.5

don't cache thumbnail

thanks tomasc! see

libvips/ruby-vips#109