Give - PayPal Pro Gateway 1.3.0

* Change: Move settings into new, consolidated PayPal settings page

* Tweak: Adjusted the plugin's settings screens code logic to work with GiveWP Core 2.5.0+ which deprecates the old methods used to register settings in this add-on.

* New: Added "give_paypal_rest_payer_info_args" for developers to customize gateway info as needed.
* Tweak: Updated the PayPal SDK to the latest version and tested.

* New: There is now an option to prefix PayPal invoice numbers to differentiate which payments were created by Give compared to other sources.
* New: Implemented the ability to process refunds within the donation payment details screen for all of PayPal Pro's APIs.
* New: Payments processed through Give + PayPal Pro can now have a customizable invoice prefix so that you can more easily identify which payments were received through the plugin.
* Fix: Updated the PayPal API library to resolve issue with the REST API not working.

* Fix: Ensure compatibility with PayPal Pro (Payflow) Fraud Protection controls. Donations flagged by PayPal's fraud filter will be marked pending and a note will be added to the payment with a link to the payment under review.

* New: Compatibility with Currency Switcher 1.1 and Give Core 2.1+ - Please update to the latest of all add-ons for maximum compatibility.
* Tweak: Minimum WP version has been bumped to 4.5+
* Fix: Added checks to ensure that Give is active prior to using gateway.

* New: PayPal Payments Pro now has additional comments that appear within the transaction details screen on the PayPal Manager dashboard to provide you better reporting and understanding that the transaction came from GiveWP, which donation form, and the URL the form was on. As well, it supports the Fee Recovery add-on and Tributes.
* New: PayPal Payments Pro transaction IDs are now linked to the payments within the Give payment details screen. This gives you an easier way to review transaction details within PayPal by clicking on them from Give's dashboard.
* Fix: Resolved issue with post transaction inquiry on payment through PayPal Payments Pro.