Handle quoteCharacter element in EML parser
Margaret and Chat said it is very common that delimiter (such as ,) is used in comment field in cvs file. However, our current EML parser couldn't handle this case now. Even quoteCharacter is used, our eml parser will still consider the delimiter character as a delimiter rather than escaping it. This will cause an problem: the column number in metadata does not match the one in data. This is new feature we need to add.