[theme] tweak slide numbering: mdash separator; no number on title
[theme] tweak slide numbering: mdash separator; no number on title

magthe/mirage-decks,samoht/mirage-decks,amirmc/mirage-decks,yomimono/mirage-decks,samoht/mirage-decks,mor1/mirage-decks,mirage/mirage-decks,mor1/mirage-decks,yomimono/mirage-decks,mirage/mirage-decks,magthe/mirage-decks,amirmc/mirage-decks