Add the markdown toolbar to the slide and poll apps

customize.dist/src/less2/include/toolbar.less

@@ -173,6 +173,7 @@
         .cp-markdown-toolbar {
             height: @toolbar_line-height;
             background-color: lighten(@bg-color, 20%);
+            display: none;
             button {
                 outline: 0;
                 color: @color;