1.1.2

• Add of_fmt to compose with existing pretty printers written in Format (#1, @Drup).
• Use a tail-recursive List.map to fix a stack overflow issue (#3, @emillon)
• Add Pp.custom_break (#4, @gpetiot)
• Add Ast sub-module to expose a stable representation for serialization, allowing to do the rendering in another process (#6, @rgrinberg)