Client Contact Methods, Employments and Identification Items now have a 'Historic' flag

A 'Historic' property has been added to the following:
Client Contact Addresses
Client Contact Methods
Client Employments
Client Identification Items

This can be set to True to indicate that either:
a) The item is not current, even though no Start and Stop dates are entered
b) The item is not current and the Start and Stop dates are estimates

Each of these business layer objects has an IsCurrent method which now accounts for the Historic flag, i.e., it will always return False if the Historic flag is True.

The forms to enter these items have been updated and a warning label added to indicate that Start and Stop dates are estimates. The built-in Summary Page Scripts have also been updated.