fix multicourse; fix bug in I4xSystem - self.filestore not set when

filestore not None.  mitxhome.html now properly automatically lists
all courses given in settings.COURSE_SETTINGS.  mitxhome now served
from multicourse.views.  optioninput.html was missing; fixed. cleaned
up access to request.session for coursename in courseware/views.py

urls.py

@@ -70,7 +70,7 @@ if settings.COURSEWARE_ENABLED:
     )
 
 if settings.ENABLE_MULTICOURSE:
-	urlpatterns += (url(r'^mitxhome$', 'util.views.mitxhome'),)
+	urlpatterns += (url(r'^mitxhome$', 'multicourse.views.mitxhome'),)
 
 if settings.QUICKEDIT:
 	urlpatterns += (url(r'^quickedit/(?P<id>[^/]*)$', 'courseware.views.quickedit'),)