button: setText() stops click event propagation

Here is an example to reproduce the issue:

``` js
modules.require(['button', 'jquery'], function(Button, $) {

$('.button').bem('button').on('click', function() {
this.setText('Button was clicked!');
});

$(document).on('click', function() {
console.log('Event was propagated to the document!');
});

});
```

Click on the `button` changes it's text, but no clicks are bubbled to document.

The issue is really annoying in case the button is set inside `popup_auclosable`, as the popup stops being closed on the first "outside" clicks after the `button` had been clicked:

``` js
{
block : 'popup',
mods : { autoclosable : true },
content : {
block : 'button',
text : 'My button'
}
}
```

/cc @dfilatov

Start with the button component's setText() behavior and reproduce the example from the issue, checking whether the click still reaches the document handler. Verify the fix with the popup autoclosable scenario: after clicking the button, an outside click should still close the popup.

Written by the indexing model from the issue text.