Issue #1992834 by alexpott: Fixed Unnecessarily setting up the array of priority formats for content negotiation within a loop.

Issue #1944472 by larowlan, quicksketch, effulgentsia: Add generic content handler for returning dialogs.

Issue #1843220 by mkadin, dawehner, Crell, effulgentsia, Wim Leers: Convert form AJAX to new AJAX API.

Issue #1716790 by attiks, sun, chx, mcjim: Fixed iOS 4 and Android 2.3 and below (webkit based browsers) return 'Unsupported Media Type' on XML in stock 8.x.

Katherine Bailey authored Apr 18, 2012 and Larry Garfield committed Apr 19, 2012

Use the getFormat() method on the request object for content type negotiation, and fallback to html in the case of no Accept header.

Add onAjax and onIframeUpload handlers to ViewSubscriber.  Add x-requested-with header to AJAX tests.