For its first production under its new moniker, the Idyllwild Actors Theatre stages Pulitizer Prize-nominee Theresa Rebeck’s provocative comedy, “Seminar.” Presented as a staged reading, with sets, costumes and props, “Seminar” stars IAT Artistic Director Howard Shangraw as Leonard, an internationally famous writer who mentors aspiring young novelists in private writing classes. Charging $5,000 to…