Fix DHT tracker overlaying bottom of the app & set z-index to force it on top if it happens again

Closes #181

app/Resources/Tracker/styles/controller.css

@@ -1,4 +1,4 @@
-#app-mount > div[class*="app-"] {
+#app-mount div[class*="app-"] {
   margin-bottom: 48px !important;
 }
 
@@ -8,6 +8,7 @@
   width: 100%;
   height: 48px;
   background-color: #fff;
+  z-index: 1000000;
 }
 
 #dht-ctrl button {

app/Resources/Tracker/styles/settings.css

@@ -7,7 +7,7 @@
   background-color: #000;
   opacity: 0.5;
   display: block;
-  z-index: 1000;
+  z-index: 1000001;
 }
 
 #dht-cfg {
@@ -20,7 +20,7 @@
   margin-top: -131px;
   padding: 8px;
   background-color: #fff;
-  z-index: 1001;
+  z-index: 1000002;
 }
 
 #dht-cfg-note {