* 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
- Added hints + hintmethod
- hintgroup compatible with loncapa spec
- also does hintfn for custom hints (can do answer history)
- GenericResponse -> LoncapaResponse
- moved response type tags into responsetype classes
- capa_problem should use __future__ division
- hints stored in CorrectMap, copied to 'feedback' in SimpleInput for display
- added correctmap.py with CorrectMap class
- messages subsumed into CorrectMap
- response get_score called with old CorrectMap so hints based on history are possible
- responsetype used to be instantiated multiple times(!) in capa_problem
now it is instantiated once, and stored in self.responders
- responsetypes.GenericResponse restructured; each superclass
show now provide setup_response (and not __init__), and may
provide get_max_score(); general __init__ provided to
clean up superclasses.
customresponses can't tell us what their answer is (there can be a
wide range of answers -- it's verified by a small program). So here
we simply ignore those fields we can't generate answers for when
doing tests against problems.
