Ability to display tips in the loading screen

customize.dist/src/less/loading.less

@@ -16,6 +16,7 @@
     .cryptofist {
         margin-left: auto;
         margin-right: auto;
+        height: 300px;
         @media screen and (max-height: @media-short-screen) {
             display: none;
         }
@@ -28,4 +29,21 @@
         }
     }
 }
-
+.cp #loadingTip {
+    position: fixed;
+    z-index: 99999;
+    top: 80%;
+    left: 0;
+    right: 0;
+    text-align: center;
+    span {
+        background-color: @bg-loading;
+        color: @color-loading;
+        text-align: center;
+        font-size: 1.5em;
+        opacity: 0.7;
+        font-family: lato, Helvetica, sans-serif;
+        padding: 15px;
+        max-width: 60%;
+    }
+}