allow overrides, set context in handler...

@lpender  This PR sets the context for the event handler as the jQuery object that `resizeSettle` was called on. It allows you to do:

```javascript
$(window).resizeSettle(function(e) {
    console.log(e);
});
```

Additionally, I deleted a couple of unused variables (`ob` and `bJustSized`) and got rid of the inner `"use strict";`.
I also switched from the single-line `if` style to the bracket style, but I don't feel that strongly about it.