Version 1.7.2 - 05.Sep.2016
* Bump VA API version to 0.39.3
* API: add support for ROI
* Add support for VP9 encoder in VA tracer
* Refine test cases
* Fix the issue of not properly terminating the parsed environment values with '\0'
  https://bugs.freedesktop.org/show_bug.cgi?id=96677