[TASK] Added getUserAgent and getReferer methods to Request class.

src/Pecee/Http/Request.php

@@ -68,6 +68,22 @@ class Request {
         return isset($_SERVER['HTTP_X_FORWARDED_FOR']) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : $_SERVER['REMOTE_ADDR'];
     }
 
+    /**
+     * Get referer
+     * @return string
+     */
+    public function getReferer() {
+        return isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '';
+    }
+
+    /**
+     * Get user agent
+     * @return string
+     */
+    public function getUserAgent() {
+        return isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : '';
+    }
+
     /**
      * Get header value by name
      * @param string $name