Renaming Namespaces and Organizing Classes

- Updated OpenId classes to be in API namespace
- Updated PP Naming Convention to PayPal Naming Convention
- FormatConverter Class got its own namespace
- Handlers are grouped in Handler namespace
- Samples and Tests Updated Accordingly

lib/PayPal/Common/PayPalResourceModel.php

@@ -0,0 +1,60 @@
+<?php
+
+namespace PayPal\Common;
+use PayPal\Handler\IPayPalHandler;
+use PayPal\Rest\ApiContext;
+use PayPal\Rest\IResource;
+use PayPal\Transport\PayPalRestCall;
+
+
+/**
+ * Class PayPalResourceModel
+ * An Executable PayPalModel Class
+ *
+ * @package PayPal\Common
+ */
+class PayPalResourceModel extends PayPalModel implements IResource
+{
+
+    /**
+     * OAuth Credentials to use for this call
+     *
+     * @var \PayPal\Auth\OAuthTokenCredential $credential
+     */
+    protected static $credential;
+
+    /**
+     * Sets Credential
+     *
+     * @deprecated Pass ApiContext to create/get methods instead
+     * @param \PayPal\Auth\OAuthTokenCredential $credential
+     */
+    public static function setCredential($credential)
+    {
+        self::$credential = $credential;
+    }
+
+
+    /**
+     * Execute SDK Call to Paypal services
+     *
+     * @param string      $url
+     * @param string      $method
+     * @param string      $payLoad
+     * @param array $headers
+     * @param ApiContext      $apiContext
+     * @param PayPalRestCall      $restCall
+     * @param array $handlers
+     * @return string json response of the object
+     */
+    protected static function executeCall($url, $method, $payLoad, $headers = array(), $apiContext = null, $restCall = null, $handlers = array('PayPal\Handler\RestHandler'))
+    {
+        //Initialize the context and rest call object if not provided explicitly
+        $apiContext = $apiContext ? $apiContext : new ApiContext(self::$credential);
+        $restCall = $restCall ? $restCall : new PayPalRestCall($apiContext);
+
+        //Make the execution call
+        $json = $restCall->execute($handlers, $url, $method, $payLoad, $headers);
+        return $json;
+    }
+}