Docs in README.

Reformat README, add some starter sections to document usage / config.

Author: xurizaemon

CRM/Core/Payment/OmnipayMultiProcessor.php

@@ -368,6 +368,13 @@ private function getCreditCardObjectParams($params) {
     return $cardFields;
   }
 
+  /**
+   * Get sensitive credit card fields.
+   *
+   * @param $params
+   *
+   * @return mixed
+   */
   private function getSensitiveCreditCardObjectOptions($params) {
     $basicMappings = array(
       'cvv' => 'cvv2',

README.md

@@ -1,16 +1,38 @@
-This extension provides a wrapper extension for payment processors.
+# CiviCRM OmniPay Multiprocessor
 
-Note that the IPN/ Silent post url that should be configured within the payment processor is
+This extension provides support for multiple payment processors in CiviCRM.
 
-http(s)://yousite/civicrm/payment/ipn/xx where xx is the payment processor ID.
+## Supported processors
 
-(I'm not quite sure the joomla & WP variants but will update when I do)
+The following payment processors are supported:
 
-How to add new payment gateways to Omnipay
+* Cybersource
+* Paybox System
+* GoPay
+* Mollie
+* Payment Express - PXPay
+* NAB Transact
+* Eway RapidDirect, Rapid & Shared
+* PayPal - Standard, Pro, REST & Express
+* Authorize AIM
 
+## Configuration
 
-1) update composer.json and run composer update
+* Visit **Administer > System Settings > Payment Processors**
+* Select the appropriate **Payment Processor Type**
+* 
 
+### IPN / Notification URL configuration
 
-2) edit CRM/Core/Payment/processors.mgd.php - check notes in that file for syntax
+If your payment processor requires configuration of an IPN or payment notification URL, 
+obtain the payment processor ID from the URL when editing the payment processor at 
+CiviCRM's Administer > System Settings > Payment Processors, then use a URL similar to 
+`https://example.org/civicrm/payment/ipn/XX` (where `https://example.org` is your actual 
+site URL and `XX` is the processor ID). 
+
+## Adding support for new payment gateways
+
+* Update `composer.json` with the required Omnipay package for your payment processor 
+  and run composer update.
+* Edit `CRM/Core/Payment/processors.mgd.php`.