Add getIdentity and hasIdentity to Authenticator.

Based on and supercedes #24. Thanks, @radicaldrew!

src/JeremyKendall/Slim/Auth/Authenticator.php

@@ -59,4 +59,24 @@ public function logout()
     {
         $this->auth->clearIdentity();
     }
+
+    /**
+     * Returns true if and only if an identity is available.
+     *
+     * @return bool
+     */
+    public function hasIdentity()
+    {
+        return $this->auth->hasIdentity();
+    }
+
+    /**
+     * Returns the authenticated identity or null if no identity is available.
+     *
+     * @return mixed|null
+     */
+    public function getIdentity()
+    {
+        return $this->auth->getIdentity();
+    }
 }

tests/JeremyKendall/Slim/Auth/Tests/AuthenticatorTest.php

@@ -86,6 +86,22 @@ public function testLogout()
         $this->authenticator->logout();
     }
 
+    public function testHasIdentityProxiesToAuthenticationService()
+    {
+        $this->auth->expects($this->once())
+            ->method('hasIdentity');
+
+        $this->authenticator->hasIdentity();
+    }
+
+    public function testGetIdentityProxiesToAuthenticationService()
+    {
+        $this->auth->expects($this->once())
+            ->method('getIdentity');
+
+        $this->authenticator->getIdentity();
+    }
+
     private function getFailureResult()
     {
         return new Result(Result::FAILURE, array(), array('FAILZORS'));