create/text: adding linespacing support
create/text: adding linespacing support

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