support contiguous stream output in notebook

Consecutive messages to stdout or stderr will not be split
into separate divs, until a new message to different stream
arrives.

Appending will only occur when the latest output is the same
as the new one. Interleaving messages will still result in
multiple divs.

IPython/frontend/html/notebook/static/js/codecell.js

@@ -251,6 +251,23 b' var IPython = (function (IPython) {'
 
 
     CodeCell.prototype.append_stream = function (json) {
+        // temporary fix: if stream undefined (json file written prior to this patch),
+        // default to most likely stdout:
+        if (json.stream == undefined){
+            json.stream = 'stdout';
+        }
+        if (this.outputs.length > 0){
+            // have at least one output to consider
+            var last = this.outputs[this.outputs.length-1];
+            if (last.output_type == 'stream' && json.stream == last.stream){
+                // latest output was in the same stream,
+                // so append directly into its pre tag
+                this.element.find('div.output_stream').last().find('pre').append(json.text);
+                return;
+            }
+        }
+        
+        // If we got here, attach a new div
         var toinsert = this.create_output_area();
         this.append_text(json.text, toinsert);
         this.element.find('div.output').append(toinsert);

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

@@ -710,7 +710,8 b' var IPython = (function (IPython) {'
         var json = {};
         json.output_type = msg_type;
         if (msg_type === "stream") {
-            json.text = utils.fixConsole(content.data + '\n');
+            json.text = utils.fixConsole(content.data);
+            json.stream = content.name;
         } else if (msg_type === "display_data") {
             json = this.convert_mime_types(json, content.data);
         } else if (msg_type === "pyout") {