⬆ Update SimplePie library.
Created by: dawnbreak
As a follow up to issue #699 (closed) update SimplePie from 1.2.1-dev (around 6years old) to current git master (1.4.4-dev). We use the master branch until the next release because it contains our patch for enclosure titles already. The other patches in the library from us can be done by configuring the SimplePie object in our code instead. Used composer to manage this library and use class autoloading. Add some unit tests for include/feedutils.php, but the interesting parts are unfortunately not testable with the current code.