A new group of developers is trying to tackle the educational app market, which has huge potential for profits, but has been hard to crack because of parent and teacher skepticism about what’s actually considered educational. Zynga, an established commercial game company responsible for hits like Farmville and Words with Friends, is hosting the non-profit accelerator in its building. Now in its second cohort, Zynga’s co.lab offers nascent game developers access to advice from experienced game, marketing and product experts.