Changes from WebPagetest 2.15:

There are quite a few big additions/improvements in this release:

Added support for an easy-deploy server running on EC2.
Mobile agent now (correctly) closes the browser between first and repeat view to match the desktop behavior.
Moved to server-side video rendering.
StatsD integration.

Web Server

Moved to server-side video rendering.
- Significantly improved video layouts.
- Support for 60fps mobile videos.
- Supports huge numbers of tests (up to 150 in the same video was tested)
Eliminated dependency on the specific version of ffmpeg for processing mobile video (now works with 1.x and 2.x).
Several additions to the install check:
- Added the version of the running release.
- Added a check for freetype (needed for server-side video rendering).
Added "error rate" reporting to the getTesters.php view.
Significantly improved the performance of the test history view if running on Linux.
Removed the Progressive JPEG recommendation (currently controversial).
Added support for an easy-deploy server running on EC2.
- Added support for automatically launching EC2 test agents.
Added support for automatically pulling the latest agent updates from the public WebPageTest instance.
Improved performance of the post-processing of mobile tests.
Added support for sharded WebPageTest servers (server ID as part of the test ID)
Added support for posting results to StatsD.
Integrated with Google Safe Browsing API for filtering of test requests (optional).
Added a hybrid work queue where beanstalkd can be used for API tests but the legacy mode (with test position) can be used for interactive tests.

Added support for reporting the DOM Content Loaded time
Agent now (correctly) closes the browser between first and repeat view to match the desktop behavior.

No significant changes (will eventually be deprecated and replaced by wptdriver).