Permission response class cleanup

Changed places that overrided the Response::testForErrors() function, so that if they pass all other validation, they now call the parent function which has been modified to return false. This also cleaned up the return values so that a boolean or error INT constant is always returned instead of having potentially void functions.

Switched out the Loader helper function for the Core::make function

Cleaned up `use` statements that didn't appear to actually be used.

Removed seemingly unused protected variables from the Response class.

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