Changes from WebPageTest 2.18:

Web Server

Added support for emulating arbitrary mobile devices (Chrome)
Updated embedded Chrome Dev Tools and Tracing UI
Added support for reporting user timing measures(API only)
Fixed target TTFB logic/grading
Added reporting of the agent Windows version in getTesters.php to prepare for Chrome deprecating < Windows 7 (6.1 actual version)
Updated EC2 AMI ID's to new/refreshed 2016 versions of the AMI's
Added support for per-connectivity or per-location test timeout settings

Improved iOS testing with 60fps video capture, tcpdump, feature compatible with Android testing
Changed test end conditions to match desktop (at onload or after 2 seconds of inactivity after onload)
Added support for testing Chrome on Android Marshmallow
Improved reliability
Updated to support Node JS 4+
Error test if Chrome crashed during testing
Added support for collecting user timing measures
Added support for the setDns script command

Updated to support latest Chrome and Firefox releases
Added HTTP/2 decode support for Firefox and IE 11 (including server push)
Support talking HTTPS to WebPageTest server (including client certificates if configured)
Reduced overhead when testing Chrome
Added support for emulating arbitrary mobile devices (Chrome)
Fixed mobile emulation viewport size to match actual device
Block automatic browser downloads
Added support for collecting user timing measures
Added reporting of the current Windows version to prepare for Chrome deprecating < Windows 7 (6.1 actual version)