Support empty string delimiter

[guyvdbroeck]

I have data files that don't have any delimiter: each character is its own column.
It would be great if CSV.jl could support empty string delimiters: CSV.File("data.txt"; delim="")
Currently it puts the entire row string into one column.

[quinnj]

I'm not sure I really see the value of using CSV.jl here, when it seems like all you need is something like:

open(file) do io
    line = readline(io)
    cols = [[line[i]] for i = 1:length(line)]
    for line in eachline(io)
        for i = 1:length(line)
            push!(cols[i], line[i])
        end
    end
end

But perhaps if we come up with some kind of API/framework for more general fixed width parsing, it could help here; I'm going to close for now as a duplicate of #601 . Feel free to comment here with other questions or to walk through your use-case in more detail if I'm misunderstanding something here.