fix Void and Number return types in afgc

Author: Joe Petviashvili

src/scope.jl

@@ -8,7 +8,8 @@ end
 
 global const scopes = Vector{Vector{AFArray}}()
 
-matches{T<:Number}(arr, except::Union{Void,Number,Array{T}}) = false
+matches(arr, except::Union{Void,Number}) = false
+matches{T<:Number}(arr, except::Array{T}) = false
 matches(arr, except::AFArray) = arr === except
 matches(arr, except::Tuple) = any(ex -> matches(arr, ex), except)
 matches{T}(arr, except::T) = error("@afgc return value can be Void, Number, Array{<:Number}, or Tuple but found $T")