The Events Calendar - Filter Bar 5.5.8

* Feature - Add check and enforce PHP 5.6 as the minimum version [116282]
* Feature - Add system to check plugin versions to inform you to update and prevent site breaking errors [116841]
* Tweak - Added filters: `tribe_not_php_version_names`
* Deprecated - The function `TribeEventsFilterViewsLoad()` and constant `REQUIRED_TEC_VERSION` along with `initAddon()` method has been deprecated in `Tribe__Events__Filterbar__View` in favor of Plugin Dependency Checking system
* Language - 7 new strings added, 20 updated, 0 fuzzied, and 1 obsoleted

* Fix - Ensure that translations are loaded before admin error messages are shown

* Fix - Improved WPML compatibility to avoid mixed languages in the additional fields dropdown. Thanks to the WPML team! [111986]
* Tweak - Add `tribe_events_filter_additional_fields_query` to make the additional field values query filterable. Thanks to David and the WPML team! [111984]