Pass null parameters

[shcrist]

Change the Exception, SkipRule, and SkipRuleType to allow for null values to be passed. Currently these values do not allow nulls. To create a configuration that accepts those values from a manifest the values must be checked in the configuration which creates a cumbersome switch statement (Eight cases) with redundant resource definitions containing the proper parameter list. If using multiple resources in a configuration it quickly becomes hundreds of lines of script. Allowing for passing a null value would allow for a single definition and move the evaluation of the parameters to the resource. In the resource the check could be part of the existing parameter validation code with a few lines of script.

[stevehose]

Shaun, this is in the pipeline and it does need to happen.