Re-enabling commented out tests (and removing old travis debugging).
Add xhprof to composer.json file & remove README.
Add xhprof option to tests:run command.
Rewrite setupProfilerXHProf to work with composer xhprof.
Get xhprof integration to work. Only setup xhprof once per php execution and correctly aggregate xhprof runs (xhprof aggregation will always normalize so we must aggregate ourselves).
Automate building of xhprof through composer install/update.
Remove changes to tests that should not be in this pull request.
Clean output of xhprof build script.
Remove completed TODO.
Replace self w/ explict class name in closure in Profiler.php.
Add quick comment descs for xhprof metrics (since they use short string names).
Exclude vendor/ from ReleaseCheckList <?php test and remove setupProfilerXHProf that are no longer necessary.
Merge pull request #6035 from piwik/5995_xhprof_improvements

Fix xhprof integration, install xhprof through composer and build xhprof through composer.