Documentation of UTF-8 encoding problems

[MarthaTenney]

When attempting to import incorrectly encoded UTF-8 characters in CSV, the import fails. This behavior is correct but it should be documented that bad UTF-8 encoding will cause an import to fail.

[McFateM]

Martha: Do you happen to have a sample of CSV data that's improperly encoded?

[MarthaTenney]

I entered this issue but think it was originally tested by @jjdipasquale -- Joanna, do you have any improperly encoded CSV data readily available? If not, I'm sure I can whip something up!