to_code -> cells_to_code to handle muliple selected cells

notebook/static/notebook/js/actions.js

@@ -243,11 +243,11 @@ define(function(require){
                 env.notebook.focus_cell();
             }
         },
-        'change-cell-to-code' : {
+        'change-cell(s)-to-code' : {
             help    : 'to code',
             help_index : 'ca',
             handler : function (env) {
-                env.notebook.to_code();
+                env.notebook.cells_to_code();
             }
         },
         'change-cell-to-markdown' : {

notebook/static/notebook/js/notebook.js

@@ -1176,7 +1176,18 @@ define(function (require) {
         var len = this.ncells();
         return this.insert_cell_below(type,len-1);
     };
-
+    
+    
+    Notebook.prototype.cells_to_code = function (indices) {
+        if (indices === undefined){
+            indices = this.get_selected_cells_indices();
+        }
+        this.untocode_backup =[];
+        
+        for (var i=0; i <indices.length; i++){
+            this.to_code(indices[i])
+        }
+    }
     /**
      * Turn a cell into a code cell.
      *