Improve offcanvas

- active by default
- fix margin
- use variables
- toggle active when tabs are added or removed

review16771002

src/sao.less

@@ -22,7 +22,7 @@
     font-size: 18px;
 }
 
-@media screen and (max-width: 768px) {
+@media screen and (max-width: @screen-xs-max) {
     .tab-form, .tab-board {
         .navbar-nav > li {
             float: left;
@@ -204,13 +204,13 @@ button {
     text-align: right;
 }
 
-@media screen and (max-width: 768px) {
+@media screen and (max-width: @screen-xs-max) {
     .dict-label {
         text-align: left;
     }
 }
 
-@media screen and (max-width: 768px) {
+@media screen and (max-width: @screen-xs-max) {
     .treeview.responsive {
         /* Override the width from Sao.View.resize */
         width: 100% !important;

src/tab.js

@@ -156,6 +156,7 @@
                 if (next) {
                     next.find('a').tab('show');
                 }
+                tabs.trigger('ready');
             }.bind(this));
         },
         _close_allowed: function() {
@@ -269,6 +270,7 @@
             Sao.View.resize(tab.el);
         });
         tab_link.tab('show');
+        tabs.trigger('ready');
     };
 
     Sao.Tab.Form = Sao.class_(Sao.Tab, {