Enable linking into the middle of sequences

* add a url that has an extra /{position} at the end
* pass it through to get_module

lms/djangoapps/courseware/module_render.py

@@ -195,7 +195,6 @@ def _get_module(user, request, location, student_module_cache, course_id, positi
                                                         descriptor.category,
                                                         shared_state_key)
 
-
     instance_state = instance_module.state if instance_module is not None else None
     shared_state = shared_module.state if shared_module is not None else None
 
@@ -254,7 +253,7 @@ def _get_module(user, request, location, student_module_cache, course_id, positi
                           # by the replace_static_urls code below
                           replace_urls=replace_urls,
                           node_path=settings.NODE_PATH,
-                          anonymous_student_id=anonymous_student_id
+                          anonymous_student_id=anonymous_student_id,
                           )
     # pass position specified in URL to module through ModuleSystem
     system.set('position', position)

lms/djangoapps/courseware/views.py

@@ -5,8 +5,6 @@ import itertools
 
 from functools import partial
 
-from functools import partial
-
 from django.conf import settings
 from django.core.context_processors import csrf
 from django.core.urlresolvers import reverse
@@ -152,7 +150,7 @@ def index(request, course_id, chapter=None, section=None,
                     course_id, request.user, section_descriptor)
                 module = get_module(request.user, request,
                                     section_descriptor.location,
-                                    student_module_cache, course_id)
+                                    student_module_cache, course_id, position)
                 if module is None:
                     # User is probably being clever and trying to access something
                     # they don't have access to.