the csv writer doesn't quote cell values even if value contains reserved characters

Given following data:
```
std::vector<std::vector<std::string>> rows =
            {
                    {"a,,,,,", "b", "c"},
                    {"1", "2", "3"},
                    {"4", "5", "6"}
            };
```
I would expect the first row to look like this:
```
"a,,,,,",b,c
```

but instead it looks like this:
```
a,,,,,,b,c
```