selection-change event does not provide all specified callback parameters

[sachinrekhi]

The selection-change event only appears to be providing range and source parameters and not providing oldRange as specified in the documentation here: http://beta.quilljs.com/docs/api/#events

Steps for Reproduction

• Visit beta.quilljs.com
• Add the following in console:

quill.on('selection-change', function(range, oldRange, source) { console.log(range); console.log(oldRange); console.log(source)})

• Click anywhere in the editor

Expected behavior:
Expect console to display range, oldRange, and source parameter values

Actual behavior:

• oldRange parameter value is actually the source paramter value
• And source variable in undefined
• (Suggesting that oldRange is just missing)

Platforms:
Chrome 51 on Mac 10.11

Version:
Quill 1.0 Beta 6