implemented tag filtering

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

de.srsoftware.cal.web/src/main/resources/index.html

@@ -10,15 +10,19 @@
         <nav />
         <div>
             <h1>Event List</h1>
-            <div id="eventnav"></div>
+            <span id="eventnav">
+                <button onclick="fetchLastMonth()">Load previous month</button>
+                <button onclick="fetchLastYear()">Load previous year</button>
+            </span>
+            <span id="tag_selection"></span>
             <table id="eventlist">
-                <tr>
+                <tr class="head">
                     <th>ID</th>
                     <th>Start</th>
                     <th>End</th>
                     <th>Location</th>
                     <th>Title</th>
-                    <th>Tags</th>
+                    <th>Tags – click to filter!</th>
                 </tr>
             </table>
         </div>