E04: add option to import delimited

[korenmiklos]

• 'Identifiers sometimes have leading zeros, in which case it may be helpful to store them as string.': This is a very important point and I would stress it even more. Students should understand the structure of the identifier before choosing the type. Otherwise, they may run into problems later where multiple groups are accidentally collapsed in one, e.g. because 01234 is read as 1234 and then cannot be distinguished from 1234. Seen against this background, you could consider to discuss the option asstring for the import statement, otherwise the damage may have already been done.

[korenmiklos]

@andrasvereckei this seems key, but can you workout an example in time for the workshop? We have space for maybe one callout box.