When a page is profiled, profile all AJAX requests too
Summary: If a page is profiled, add an "X-Phabricator-Profiler" header to all Ajax requests, and profile those too.
Test Plan: Profiled a page, checked Darkconsole, saw profiles for everything.
Reviewers: vrana, btrahan
Reviewed By: vrana
CC: aran
Differential Revision: https://secure.phabricator.com/D4885