Enabled Billing Plans and Agreements APIs

- Added API Classes, Samples, and Tests
- Updated Functional Tests
- Updated Documentation with new SDK Name
- Updated Few Samples to use newer nicer result page

sample/billing/CreatePlan.php

@@ -0,0 +1,72 @@
+<?php
+
+// # Create Plan Sample
+//
+// This sample code demonstrate how you can create a billing plan, as documented here at:
+// https://developer.paypal.com/webapps/developer/docs/api/#create-a-plan
+// API used: /v1/payments/billing-plans
+
+require __DIR__ . '/../bootstrap.php';
+use PayPal\Api\Plan;
+use PayPal\Api\PaymentDefinition;
+use PayPal\Api\MerchantPreferences;
+use PayPal\Api\Currency;
+use PayPal\Api\ChargeModel;
+
+// Create a new instance of Plan object
+$plan = new Plan();
+
+// # Basic Information
+// Fill up the basic information that is required for the plan
+$plan->setName('T-Shirt of the Month Club Plan')
+    ->setDescription('Template creation.')
+    ->setType('fixed');
+
+// # Payment definitions for this billing plan.
+$paymentDefinition = new PaymentDefinition();
+
+// The possible values for such setters are mentioned in the setter method documentation.
+// Just open the class file. e.g. lib/PayPal/Api/PaymentDefinition.php and look for setFrequency method.
+// You should be able to see the acceptable values in the comments.
+$paymentDefinition->setName('Regular Payments')
+    ->setType('REGULAR')
+    ->setFrequency('Month')
+    ->setFrequencyInterval("2")
+    ->setCycles("12")
+    ->setAmount(new Currency(['value' => '100', 'currency' => 'USD']));
+
+// Charge Models
+$chargeModel = new ChargeModel();
+$chargeModel->setType('SHIPPING')
+    ->setAmount(new Currency(['value' => '10', 'currency' => 'USD']));
+
+$paymentDefinition->setChargeModels(array($chargeModel));
+
+$merchantPreferences = new MerchantPreferences();
+$baseUrl = getBaseUrl();
+$merchantPreferences->setReturnUrl("$baseUrl/ExecuteAgreement.php?success=true")
+    ->setCancelUrl("$baseUrl/ExecuteAgreement.php?success=false")
+    ->setAutoBillAmount("YES")
+    ->setInitialFailAmountAction("CONTINUE")
+    ->setMaxFailAttempts("0")
+    ->setSetupFee(new Currency(['value' => '1', 'currency' => 'USD']));
+
+
+$plan->setPaymentDefinitions(array($paymentDefinition));
+$plan->setMerchantPreferences($merchantPreferences);
+
+// For Sample Purposes Only.
+$request = clone $plan;
+
+// ### Create Plan
+try {
+    $output = $plan->create($apiContext);
+} catch (PayPal\Exception\PPConnectionException $ex) {
+    echo "Exception: " . $ex->getMessage() . PHP_EOL;
+    var_dump($ex->getData());
+    exit(1);
+}
+
+ResultPrinter::printResult("Created Plan", "Plan", $output->getId(), $request, $output);
+
+return $output;