add button that updates the calendar with another source. tooltip format change, multiple color

commit frequently pls

index.html

@@ -9,8 +9,12 @@
 </head>
 
 <body>
-    <input type="text" id="ics_file">
-    <input type="button" value="hi" id="ics_run">
+    <div class="flex_input">
+        <input type="text" id="ics_file">
+        <input type="button" value="new calendar" id="ics_run">
+        <input type="button" value="add a calendar" id="ics_add">
+    </div>
+
     <div id="calendar"></div>
 </body>