disable loading window buttons on mode selection

gui/startup/index.html

@@ -29,17 +29,20 @@
           height="100" />
         <div id="agamaModeStatus">Choose Agama mode</div>
         <button
+          id="nativeOnlyBtn"
           onClick="closeMainWindow()"
           class="btn btn-primary margin-right-20 btn-mode">
           <img src="../EasyDEX-GUI/assets/mainWindow/img/fa-cube.png"> Native only
         </button>
         <button
+          id="normalStartBtn"
           onClick="normalStart()"
           class="btn btn-primary btn-mode">
           <img src="../EasyDEX-GUI/assets/mainWindow/img/fa-cubes.png"> Normal start
         </button>
         <div class="margin-top-20">
           <button
+            id="settingsBtn"
             onClick="openSettingsWindow()"
             class="btn btn-info btn-mode">
             <img src="../EasyDEX-GUI/assets/mainWindow/img/fa-cogs.png"> Settings