MANCHESTER, N.H. - Designer bars studded with single-source cacao beans are displayed in an antique jewel case like edible artifacts from a Mayan mirage. It’s a sight that could leave the most jaded food snob breathless, and would not be out of place in a small shop in Paris. Richard Tango-Lowy is changing the taste and timbre of this New Hampshire city with his Dancing Lion Chocolate. Inside the months-old cafe, drinking chocolate changes daily, accented with cardamom, cinnamon, and exotic flavors such as kaffir lime. “ ‘Chocolate is Art’ is our tagline,’’ says Tango-Lowy, who perfected his passion at Ecole Du Grand Chocolat Valrhona in Tain L’Hermitage, France.