Added dropdown submenu CSS

IPython/html/static/notebook/less/menubar.less

@@ -35,3 +35,11 @@ ul#help_menu li a{
 ul#menus {
   float: left;
 }
+
+// http://www.bootply.com/86684
+.dropdown-submenu{position:relative;}
+.dropdown-submenu>.dropdown-menu{top:0;left:100%;margin-top:-6px;margin-left:-1px;-webkit-border-radius:0 6px 6px 6px;-moz-border-radius:0 6px 6px 6px;border-radius:0 6px 6px 6px;}
+.dropdown-submenu:hover>.dropdown-menu{display:block;}
+.dropdown-submenu>a:after{display:block;content:" ";float:right;width:0;height:0;border-color:transparent;border-style:solid;border-width:5px 0 5px 5px;border-left-color:#cccccc;margin-top:5px;margin-right:-10px;}
+.dropdown-submenu:hover>a:after{border-left-color:#ffffff;}
+.dropdown-submenu.pull-left{float:none;}.dropdown-submenu.pull-left>.dropdown-menu{left:-100%;margin-left:10px;-webkit-border-radius:6px 0 6px 6px;-moz-border-radius:6px 0 6px 6px;border-radius:6px 0 6px 6px;}

IPython/html/static/notebook/less/toolbar.less

@@ -21,6 +21,7 @@
 
 .toolbar .btn-group {
   margin-top: 0px;
+  margin-left: 5px;
 }
 
 .toolbar-inner {
@@ -30,4 +31,8 @@
 
 #maintoolbar {
   margin-bottom: 0px;
-}
+}
+
+#maintoolbar .navbar-text {
+  float: none;
+}