Features/Changes

• Lib: add missing File.blob constructor (fix #630)
• Runtime: hash support for custom blocks
• Runtime: weak.js loaded by default
• Compiler: compile an OCaml program into a named javascript function (fix #599)
• Misc: move ppx_deriving_json in its own opam package (Rudi Grinberg)
• Compiler: static eval of float negation
• Compiler: improve constant sharing.
• Ppx: add support for writeonly_prop and optdef_prop in object literal.

Bug fixes

• Compiler: fix code generation of unary ops (missing space).
• Compiler: fix static eval of conditions (fix #616)
• Compiler: fix code generation for OCaml GPR#1568
• Runtime: fix bug found using the closure compiler (#644)