Fix bogus usage of menu_get_active_trail().
Issue #1661110 by amateescu, Rob Loach: Replace the usage of $_GET['q'] with current_path().
Issue #1661104 by amateescu, Rob Loach: Fixed the class autoloading.
Issue #1661052 by Rob Loach: Fixed the link being output.
Issue #1715426 by Dave Reid, erikwebb, msonnabaum: Don't load xhprof.inc unnecessarily.
Issue #1803858 by erikwebb, jrbeeman: Make profiling settings dependent on enabled setting.