capture the error message and traceback and show this as the problem text.

main.html now includes mathjax_include for all mathjax stuff
problem.js refreshes mathjax formulas on change
all previous *_fromjs renamed to *_dynamath, eg textline_dynamath

to use logging; added DEBUG attr to XModule class

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

problem.js (commented out)

(see courseware.views.quickedit_git_reload)