NEW YORK — Jeff Skoll’s Participant Prods. has partnered with ThinkFilm and MTV Films on the upcoming release of Henry Alex Rubin and Dana Adam Shapiro’s “Murderball.”Rough-and-tumble docu concerns quadriplegics who play rugby. Film has generated plenty of buzz on the festival circuit, picking up two prizes at the Sundance Film Festival. A&E IndieFilms also is a partner on “Murderball,” bowing July 8. Skoll, founder of eBay, launched his production company in 2004 with the intent of developing or partnering on film projects with socially conscious leanings.