Missing data

I've been trying out this library as I jump into learning Julia and I'm wondering what support there is for missing values in the dataset. Any recommendations that you have based on your experience for how to deal with these missing values would be very helpful.

julia> model = build_forest(labels, features, 3, 10)

exception on 1: ERROR: no method convert(Type{Bool}, NAtype)
in setindex! at array.jl:298
in bitcache_lt at broadcast.jl:366
in .< at broadcast.jl:382
in build_tree at .julia/v0.3/DecisionTree/src/DecisionTree.jl:153
in build_tree at .julia/v0.3/DecisionTree/src/DecisionTree.jl:171
in anonymous at no file:237
in anonymous at multi.jl:1263
in run_work_thunk at multi.jl:613
in run_work_thunk at multi.jl:622
in anonymous at task.jl:6
ERROR: no method convert(Type{Node}, MethodError)
in copy! at abstractarray.jl:149
in convert at array.jl:209
in build_forest at .julia/v0.3/DecisionTree/src/DecisionTree.jl:239
in build_forest at .julia/v0.3/DecisionTree/src/DecisionTree.jl:232

Start with the reported build_forest(labels, features, 3, 10) reproduction and inspect build_tree and build_forest at .julia/v0.3/DecisionTree/src/DecisionTree.jl lines 153, 171, 232, and 239. Determine the intended behavior for missing values and define completion by handling the example without the reported conversion errors, with coverage for the supported behavior.