Malformed today's market calibration CSV due to commas in calendars

[gbfredrik]

Hi,
Small issue here. JointCalendar names are not wrapped with quotes when written to CSVs, causing parsing failures when the CSV separator is also a comma. See the below example:

Instead, the output should be something like:

We'll try to do something about it, but please let us know if you get there first :)

[pcaspers]

Please do go ahead 😃