implement BrowserWindow-API functions

ElectronNET.API/Entities/LoadURLOptions.cs

@@ -0,0 +1,22 @@
+namespace ElectronNET.API.Entities
+{
+    public class LoadURLOptions
+    {
+        /// <summary>
+        /// A HTTP Referrer url.
+        /// </summary>
+        public string HttpReferrer { get; set; }
+
+        /// <summary>
+        /// A user agent originating the request.
+        /// </summary>
+        public string UserAgent { get; set; }
+
+        /// <summary>
+        /// Base url (with trailing path separator) for files to be loaded by the data url.
+        /// This is needed only if the specified url is a data url and needs to load other
+        /// files.
+        /// </summary>
+        public string BaseURLForDataURL { get; set; }
+    }
+}