Add the ValidateListUniqueStrings function, which is a ValidateFunc that
ensures a list has no duplicate items in it. It's useful for when a list
is needed over a set because order matters, yet the items still need to
be unique.
This adds a ValidateRegexp validation helper to check to see if a field
has a valid regular expression.
Includes test for good regexp, and test for bad regexp.
Chris Marchesi