CI 1.7 form_validation bug regarding callbacks

[eluser]skunkbad[/eluser]
This had messed me up in the past, but it really can't be considered a bug, because the docs don't say that you can use more than one callback per field when setting up your rules. The docs should say there is a limit of one callback per rule to avoid confusion, but this has been covered in the forum many times, so it wouldn't take long for somebody to learn what they are doing wrong.