reordered code to move branches far from what they depend on and cleaned comments
reordered code to move branches far from what they depend on and cleaned comments

lovell/libvips,lovell/libvips,leiyangyou/libvips,mcanthony/libvips,wishabi/libvips,leiyangyou/libvips,wishabi/libvips,lovell/libvips,wishabi/libvips,jcupitt/libvips,jcupitt/libvips,jcupitt/libvips,mcanthony/libvips,mcanthony/libvips,leiyangyou/libvips,lovell/libvips,leiyangyou/libvips,jcupitt/libvips,wishabi/libvips,mcanthony/libvips