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

tests/PayPal/Test/Exception/PayPalMissingCredentialExceptionTest.php

@@ -0,0 +1,42 @@
+<?php
+use PayPal\Exception\PayPalMissingCredentialException;
+
+/**
+ * Test class for PayPalMissingCredentialException.
+ *
+ */
+class PayPalMissingCredentialExceptionTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var PayPalMissingCredentialException
+     */
+    protected $object;
+
+    /**
+     * Sets up the fixture, for example, opens a network connection.
+     * This method is called before a test is executed.
+     */
+    protected function setUp()
+    {
+        $this->object = new PayPalMissingCredentialException;
+    }
+
+    /**
+     * Tears down the fixture, for example, closes a network connection.
+     * This method is called after a test is executed.
+     */
+    protected function tearDown()
+    {
+    }
+
+    /**
+     * @test
+     */
+    public function testErrorMessage()
+    {
+        $msg = $this->object->errorMessage();
+        $this->assertContains('Error on line', $msg);
+    }
+}
+
+?>