Add return types to PhpFlickrService methods

* Add return types to PhpFlickrService methods.
* Remove an unused import.
* Add `vendor/` directory to Phan.

Fixes #79

Author: samwilson

.phan/config.php

@@ -3,6 +3,7 @@
 return [
     'directory_list' => [
         'src',
+        'vendor',
     ],
     'exclude_file_regex' => '@^vendor/.*/(tests?|Tests?)/@',
     'exclude_analysis_directory_list' => [

src/Oauth/PhpFlickrService.php

@@ -7,7 +7,6 @@
 use OAuth\Common\Http\Uri\Uri;
 use OAuth\Common\Http\Uri\UriInterface;
 use OAuth\Common\Storage\TokenStorageInterface;
-use OAuth\OAuth1\Service\AbstractService;
 use OAuth\OAuth1\Service\Flickr;
 use OAuth\OAuth1\Signature\SignatureInterface;
 
@@ -37,17 +36,17 @@ public static function setBaseUrl($baseUrl)
         static::$baseUrl = rtrim($baseUrl, '/');
     }
 
-    public function getRequestTokenEndpoint()
+    public function getRequestTokenEndpoint(): UriInterface
     {
         return new Uri(static::$baseUrl . '/oauth/request_token');
     }
 
-    public function getAuthorizationEndpoint()
+    public function getAuthorizationEndpoint(): UriInterface
     {
         return new Uri(static::$baseUrl . '/oauth/authorize');
     }
 
-    public function getAccessTokenEndpoint()
+    public function getAccessTokenEndpoint(): UriInterface
     {
         return new Uri(static::$baseUrl . '/oauth/access_token');
     }

src/PhpFlickr.php

@@ -26,6 +26,7 @@
 use OAuth\Common\Consumer\Credentials;
 use OAuth\Common\Http\Client\CurlClient;
 use OAuth\Common\Http\Uri\Uri;
+use OAuth\Common\Http\Uri\UriInterface;
 use OAuth\Common\Storage\Memory;
 use OAuth\Common\Storage\TokenStorageInterface;
 use OAuth\OAuth1\Service\Flickr;
@@ -281,8 +282,8 @@ public function getOauthService($callbackUrl = 'oob')
         $factory->registerService('Flickr', PhpFlickrService::class);
         $factory->setHttpClient(new CurlClient());
         $storage = $this->getOauthTokenStorage();
-        /** @var PhpFlickrService $flickrService */
         $this->oauthService = $factory->createService('Flickr', $credentials, $storage);
+        assert($this->oauthService instanceof PhpFlickrService);
         return $this->oauthService;
     }
 
@@ -295,7 +296,7 @@ public function getOauthService($callbackUrl = 'oob')
      * @param string $perm One of 'read', 'write', or 'delete'.
      * @param string $callbackUrl Defaults to 'oob' ('out-of-band') for when no callback is
      * required, for example for console usage.
-     * @return Uri
+     * @return UriInterface
      */
     public function getAuthUrl($perm = 'read', $callbackUrl = 'oob')
     {