Merge pull request #309 from MITx/feature/tutorials_fix

Add optional hide_from_toc attribute to XML elements

common/lib/xmodule/xmodule/x_module.py

@@ -104,7 +104,8 @@ class HTMLSnippet(object):
         """
         Return the html used to display this snippet
         """
-        raise NotImplementedError("get_html() must be provided by specific modules")
+        raise NotImplementedError("get_html() must be provided by specific modules - not present in {0}"
+                                  .format(self.__class__))
 
 
 class XModule(HTMLSnippet):

common/lib/xmodule/xmodule/xml_module.py

@@ -88,7 +88,7 @@ class XmlDescriptor(XModuleDescriptor):
     # The attributes will be removed from the definition xml passed
     # to definition_from_xml, and from the xml returned by definition_to_xml
     metadata_attributes = ('format', 'graceperiod', 'showanswer', 'rerandomize',
-        'start', 'due', 'graded', 'name', 'slug')
+        'start', 'due', 'graded', 'name', 'slug', 'hide_from_toc')
 
     # A dictionary mapping xml attribute names to functions of the value
     # that return the metadata key and value