`showAlert` gets an id (what to display, e.g. "nightly.notextbox.message") and pops up an alert.

`showConfirmEx` (not the best name, I know, but I was unable to get better) - gets a text and it is widely configurable.
Of course, you could use it as simple as `showAlert`, if you like.

I decided to implement a new function is due to this difference: `showAlert` takes an id (from `nightly.properties`), the new function takes a text as argument.

If you want to replace `showAlert` instead creating a new one, then the usages should be updated to use `nightly.getString`.
It's OK to me, but please ask for it! :)