Add energy indicator in the web interface.

code/html/index.html

@@ -220,6 +220,11 @@
                                     <input class="pure-u-1 pure-u-sm-3-4" type="text" name="pwrFactor" post="%" readonly />
                                 </div>
 
+                                <div class="pure-g module module-hlw">
+                                    <label class="pure-u-1 pure-u-sm-1-4" for="pwrFactor">Energy</label>
+                                    <input class="pure-u-1 pure-u-sm-3-4" type="text" name="pwrEnergy" post=" Wh" readonly />
+                                </div>
+
                                 <div class="pure-u-1 state">
 
                                     <div class="pure-u-1 pure-u-sm-1-4">Manufacturer</div>