Added __html__() method to the HTML class so that other Python modules

will know not to escape special characters.  See http://bit.ly/13MaPq6
for an example of how it gets used.

IPython/core/display.py

@@ -337,6 +337,14 b' class HTML(DisplayObject):'
     def _repr_html_(self):
         return self.data
 
+    def __html__(self):
+        """
+        This method exists to inform other HTML-using modules (e.g. Markupsafe,
+        htmltag, etc) that this object is HTML and does not need things like
+        special characters (<>&) escaped.
+        """
+        return self._repr_html_()
+
 
 class Math(DisplayObject):