Removing unwanted Exception class
Let RestException extend directly from /Exeption
Added getErrorMessage method to RestException that composes the error message to be returned with the response
iRespond interface updated to use RestException as the only parameter to create the error response
Responder class updated to implement the modified iRespond interface
handleError method is replaced with handleException which takes any Exception, constructs RestException if needed and then passes the RestException all the way to Responder.

All calls to handleError were replaced with RestExceptions instead