Tracking API: when overriding the request datetime with an invalid token_auth, don't track the request (#10899)

* refs #10890 ignore tracking requests with custom timestamp, accept timestamps up to 1 day in past, added config for timestamps that require auth

* fix test

* update travis yml

* update travis

* update travis

* fix test

* added changelog entry

* .travis.yml file is out of date, auto-updating .travis.yml file.

* .travis.yml file is out of date, auto-updating .travis.yml file.

* .travis.yml file is out of date, auto-updating .travis.yml file.

* .travis.yml file is out of date, auto-updating .travis.yml file.

* .travis.yml file is out of date, auto-updating .travis.yml file.

* .travis.yml file is out of date, auto-updating .travis.yml file.

* New config.ini.php setting: `tracking_requests_require_authentication_when_custom_timestamp_newer_than`

PHP 7: when there is a fatal error in API request processing, display the original error in the api response (#10406)

* PHP 7: when there is a fatal error in API request processing, display  the original error

* PHP 7 compatibility