[julia-users] isa should be user friendlier

[J Luis]

julia> isa(1.0f0, Float32)
true

julia> isa([1.0f0], Float32)
false

julia> isa([1.0f0], Array{Float32})
true

It means that to know the data type one must first test if the variable is 
scalar or array. Not nice. I find the Matlab equivalent much easier to use.