“Quinografía,” a portrait of the famously timid Mafalda cartoonist Quino, and “Habana Libre,” a take on rebellious youth in Cuba, look like potential standouts at Ventana Docs, a selection of 12 doc features from across Latin America and Spain.   A notable number have been developed at prestigious labs, whether Sundance Festival programs (“Bleeding Heart,” “Violent-House-Fiction”) […]