Jason Blum’s Blumhouse Productions and China’s Tang Media Partners have set an agreement to co-develop and co-finance a series of Chinese-language horror/thriller features beginning with American Nightmare, an LA-based project. The films will be made in both the Middle Kingdom and the U.S. and released in China, the partners said at the Shanghai International Film Festival today. The pact is designed to capitalize on China's rapid box office growth and audience demand for…