Sync version numbers
Add support for Rest and Spread Arguments
According to the ES7 proposal at
https://gist.github.com/sebmarkbage/aa849c7973cb4452c547
Add XJSSpreadAttribute syntax

https://github.com/reactjs/react-future/blob/master/01%20-%20Core/08%20-%20Transferring%20Props.js
Change XJSSpreadAttribute signature to use "argument" property
This brings it inline with other spread AST nodes.
Made some of the tests expression statements instead of declarations
Added test for leading attributes and spread in closing element
Merge pull request #22 from sebmarkbage/spread

Object Rest/Spread Properties