map is broken on v0.0.5

[davidagold]

This will be addressed by #128 , but it needs to be noted:

               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.5.0-dev+5156 (2016-07-05 13:54 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit 0b22a01* (5 days old master)
|__/                   |  x86_64-apple-darwin15.5.0

julia> using NullableArrays

julia> map(sin, NullableArray(Int[1]); lift=true)
ERROR: UndefVarError: f not defined
 in (::NullableArrays.##_F_#35#39)(::Bool, ::Function, ::NullableArrays.NullableArray{Int64,1}) at /Users/David/.julia/v0.5/NullableArrays/src/map.jl:90
 in (::NullableArrays.#kw##_F_#38)(::Array{Any,1}, ::NullableArrays.#_F_#38, ::NullableArrays.NullableArray{Int64,1}) at ./<missing>:0
 in (::NullableArrays.##map#7#8{Dict{Int64,Dict{Union{DataType,Function},Function}}})(::Bool, ::Function, ::Base.#sin, ::NullableArrays.NullableArray{Int64,1}, ::Vararg{NullableArrays.NullableArray{Int64,1},N}) at /Users/David/.julia/v0.5/NullableArrays/src/map.jl:172
 in (::Base.#kw##map)(::Array{Any,1}, ::Base.#map, ::Base.#sin, ::NullableArrays.NullableArray{Int64,1}) at ./<missing>:0
 in eval(::Module, ::Any) at ./boot.jl:234
 in macro expansion at ./REPL.jl:92 [inlined]
 in (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at ./event.jl:46