A simple interface for handling validation of rules. Validation results are returned in a
ValidationResults object which consists of a series of error messages regarding the
rule. The user who is adding or editing the rule is passed to validate as well as the
rule to be validated.
author: ewestfal
Validates the rule within the given RuleValidationContext.
a ValidationResults object representing the results of the validation, if this isempty or null this signifies that validation was successful.