fixes Bug 930324 - added processed_crash redaction system

accepting that sensitive information is going to be in the processed_crash, we need a way to fetch redacted and unredacted copies of the processed_crash.

This PR adds the Redactor as a configurable class option on all crash storage classes.  Its is responsible for removing sensitive keys from the processed_crash as it returned from any crashstorage implementation.  In all instances of the crashstorage classes, the ```get_processed``` method has been replaced with ```get_unredacted_processed``` methods.  These do no filtering.  The crashstorage base class now implements ```get_processed``` by calling the derived ```get_unredacted_processed``` methods, passing the results through the redactor and then return a redacted version of the processed_crash.  

To clients of the crashstorage classes there has been no change in behavior of the ```get_processed``` method.  It always has returned a "safe" version of the processed_crash and continues to do so now.