don’t start output areas collapsed

this sets metadata.collapsed = true metadata on cells with no output

causing churn in notebook files

notebook/static/notebook/js/outputarea.js

@@ -77,7 +77,7 @@ define([
         this.prompt_overlay.addClass('out_prompt_overlay prompt');
         this.prompt_overlay.attr('title', 'click to expand output; double click to hide output');
         
-        this.collapse();
+        this.expand();
     };
 
     /**
@@ -976,6 +976,7 @@ define([
             this._display_id_targets = {};
             this.trusted = true;
             this.unscroll_area();
+            this.expand();
             return;
         }
     };