Enter on empty list item creates api change instead of user change

[benbro]

[Describe the issue]
When pressing Enter in a line with empty list item, the list annotation is removed but the text-change event gets 'api' source instead of 'user' source.

Steps for Reproduction

1. Visit http://beta.quilljs.com/
2. select all text (ctrl+a) and remove it (backspace)
3. write text-change source and delta in the console:

quill.on('text-change', function(delta, oldDelta, source) {
  console.log(source, delta);
});

1. click on the ordered list button
2. press Enter

Expected behavior: [expected]
All the text-change sources in the console should be 'user'

Actual behavior: [actual]
The last source is 'api'

Platforms:
Firefox 47 on Windows 7

Version: [version]
1.0-beta.4

[benbro]

It must be the quickest fix in the history of github :)

[benbro]

The clear formatting button has the same issue.
When selecting some text and clicking on the T_x button the text-change event source is 'api' instead of 'user'

To reproduce:

1. Visit http://beta.quilljs.com/docs/formats/
2. Click on the Bold (B) button
3. type 'a'
4. select the bold letter 'a'
5. click on the clear formatting button T_x

The last text-change event has 'api' source