- if no answer given, then symbolicresponse + customrepsonse now
  give an error message, instead of doing nothing
- in capa_module if lcp.grade_answers fails, in DEBUG mode display
  alert with useful error message

* use clearer names for the two status strings passed to js
* add functions to do canonical conversion of progress to js string
* fix updating bug in sequence.coffee
* add some todo comments and other docs to make future expansion easier

* add module_from_xml param to I4xSystem
* use it to implement xmodule.get_children()
* fix a few comments here and there
* Render-time progress display for seq and vertical modules.
  - Computes fraction of subproblems done.
* Pass problem state back to js during ajax calls.
* general cleanup in capa_module.py
* add progress_changed and progress fields to json returned from each ajax handler

* Coffeescript changes to hook up sequence tracking of problem progress

* net result: sequence 'a' tags now have a progress class
* properly set css class on initial load
* fire event when progress changes after ajax calls
* also save state in 'progress' property of problems-wrapper tag
* event handler finds those tags, computes updated progress

Add categories and XModuleDescriptors for all module types that are used at the top level of a course

* Change looping code style in seq_module
* Clone and keep the latest version of jasmine-jquery locally
* Use django-pipeline asset tags

urls, courseware.{views,module_render}, comments added to seq_module

Refactor for reusability: x_modules take common parameters as an object. capa_problem to take a file object and not filename.

--HG--
branch : pmitros-subtitles

Semi-generic registration mechanism for modules. Still need to clean up references in content_parser

--HG--
branch : pmitros-mod-template