store cell toolbar preset in notebook metadata

allows resume on load

IPython/html/static/notebook/js/celltoolbar.js

@@ -214,7 +214,7 @@ var IPython = (function (IPython) {
      *
      *      CellToolbar.activate_preset('foo.foo_preset1');
      */
-    CellToolbar.activate_preset= function(preset_name){
+    CellToolbar.activate_preset = function(preset_name){
         var preset = CellToolbar._presets[preset_name];
 
         if(preset != undefined){

IPython/html/static/notebook/js/maintoolbar.js

@@ -147,9 +147,11 @@ var IPython = (function (IPython) {
                 var val = $(this).val()
                 if (val =='') {
                     IPython.CellToolbar.global_hide();
+                    delete IPython.notebook.metadata.celltoolbar;
                 } else {
                     IPython.CellToolbar.global_show();
                     IPython.CellToolbar.activate_preset(val);
+                    IPython.notebook.metadata.celltoolbar = val;
                 }
             });
         // Setup the currently registered presets.

IPython/html/static/notebook/js/notebook.js

@@ -1958,7 +1958,14 @@ var IPython = (function (IPython) {
             this.start_session();
         }
         // load our checkpoint list
-        IPython.notebook.list_checkpoints();
+        this.list_checkpoints();
+        
+        // load toolbar state
+        if (this.metadata.celltoolbar) {
+            IPython.CellToolbar.global_show();
+            IPython.CellToolbar.activate_preset(this.metadata.celltoolbar);
+        }
+        
         $([IPython.events]).trigger('notebook_loaded.Notebook');
     };