Code example mistake at homepage

[nicasi]

Hey thanks for this cool plugin, we're 2015 and the code is still going strong with jQuery 1.11.1.

I noticed a tiny error at the github homepage of the plugin here: https://github.com/beezee/djax#dom-replacement-callbacks-optional

Following line $oldEl.replaceWith($content);

should be $oldEl.replaceWith($newEl);