[DataFrame] Allow quote escaping

[luisquintanilla]

Loading data from a column containing quotes inside a string shouldn't break.

"this is one column value which includes a "" character" 

[dakersnar]

I believe this issue has been solved already for LoadCsv (I added unit tests to confirm this). However, I found bugs related to this in WriteCsv. I have a fix that will go up as soon as #6303 is merged.