[fix] settings.yml: make sure all engine names are lower case
[fix] settings.yml: make sure all engine names are lower case

jcherqui/searx,dalf/searx,asciimoo/searx,jcherqui/searx,jcherqui/searx,asciimoo/searx,asciimoo/searx,dalf/searx,jcherqui/searx,dalf/searx,asciimoo/searx,dalf/searx