Hide menu and show it when hitting button.

Closes https://gitlab.com/autonomic-cooperative/autonomic-cooperative.gitlab.io/issues/28.

src/assets/js/main.js

@@ -61,6 +61,8 @@
         offset: $header.outerHeight()
       });
 
+    $("#menu").show();
+
     // Menu.
     $('#menu')
       .append('<a href="#menu" class="close"></a>')

src/assets/styles/components/_menu.scss

@@ -21,6 +21,7 @@
 }
 
 #menu {
+  display:none;
   @include vendor('transform', 'translateX(20em)');
   @include vendor('transition', 'transform #{_duration(menu)} ease');
   -webkit-overflow-scrolling: touch;