Data error checking

[eemeli]

From Karl-Johan Norén:

Right now, KonOpas has no real error checking for the data integrity, and I think having such an utility would be worthwhile, especially if one uses a spreadsheet as the backend (like I do).

Some examples of errors that should be relatively easy to detect:

• Dates and times are correctly formed
• No duplicate IDs

Slightly more convoluted:

• Check that the programme items and the people are properly cross-referenced
• Check validity of image links

Where to put this is another question. Right in the CSV-parsers is one option, or make it into a separate utility.