Escaping CSV headings

In **Format.php** only CSV data is escaped, escaping headings -as well- would resolve an issue of a heading including a comma

*Sample of Old O/P*
```
id,Heading with, Comma
"1","data with, comma"
```

*Sample of New O/P*
```
"id","Heading with, Comma"
"1","data with, comma"
```