Rewrite the `callAll` and `aCallAll` functions to support all
reasonable hook behaviors and to report errors for unreasonable
behaviors (e.g., calling the callback twice).
Now a hook function like the following works as expected when invoked
by `aCallAll`:
```
exports.myHookFn = (hookName, context, cb) => {
cb('some value');
return;
};
```
Richard Hansen