Generalized map loader

return function (mapfile, terrains)
    local new = {}
    for line in io.lines(mapfile) do
        local h = 1
        local row = {}
        for point in line:gmatch('.') do
            row[h] = terrains[point]
            h = h + 1
        end
        table.insert(new, row)
    end
    return new
end