Do not show scheduler tab in Web UI if build without scheduler support (#527)

code/espurna/scheduler.ino

@@ -17,6 +17,7 @@ Adapted by Xose Pérez <xose dot perez at gmail dot com>
 
 void _schWebSocketOnSend(JsonObject &root){
 
+    root["schVisible"] = 1;
     root["maxScheduled"] = SCHEDULER_MAX_SCHEDULES;
     JsonArray &sch = root.createNestedArray("schedule");
     for (byte i = 0; i < SCHEDULER_MAX_SCHEDULES; i++) {

code/html/index.html

@@ -102,7 +102,7 @@
                             <a href="#" class="pure-menu-link" data="panel-relay">SWITCHES</a>
                         </li>
 
-                        <li class="pure-menu-item module module-relay">
+                        <li class="pure-menu-item module module-sch">
                             <a href="#" class="pure-menu-link" data="panel-schedule">SCHEDULE</a>
                         </li>