Popup Maker - Exit Intent Popups 1.4.0

* Feature: Added multiple new exit intent methods for all devices.
* Mouse Leave - Traditional exit intent that detects mouse movements towards the close button, address bar or back button.
* Lost Browser Focus - When the user switches tabs, apps, or clicks anywhere outside of the current page.
* Back Button - Detects users clicking the back button and shows a popup.
* Link Click - Detects when users are intending to click a targeted link and triggers a popup.
* Time Delay (mobile fallback) - A simple time delay fallback for mobile devices.
* Mobile Scroll - Detects when users scroll down partially on the page then quickly back up showing their intent to leave.

Fix: Corrected activation routine issues that could prevent version number storage.

* Updated for full Popup Maker v1.7 support.
- Leveraged the new AssetCache reducing the need to load an extra JS file for this extension.
- Autoloader
- Upgrade routines.
* Fix: Added check to make sure FireFox select fields don't trigger the exit trigger.