Change break line symbol for item description

Issue description

Request to change the new-line character in item's description text to something else, as I find myself wanting to put commas in a large number of item descriptions, and other symbols like '~', for instance, essentially never.

Issue comments

To support the backward compatibility, we have kept the , as the line separator. Instead, we added a new option to escape the separator. If one wants to insert a comma in the description, he writes \, instead of ,.

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