show author name in question search results on exam edit view
fix IE8 mega-crash.

The root of the problem, after an hour or two of head-banging, was:
<label> ... </span>
OK, I made a mistake, but don't crash the entire browser!

This also applies the fix from http://www.nickyeoman.com/blog/html/118-html5-tags-in-ie8 to get the new <section> tag in IE8.
question edit: Call Numbas.tryInit *after* defining Question()

I'm fairly sure this fixes #117, finally.
fix mismatched <label> tag in noneditable question view

ref #117
fix "invalid argument" error in question noneditable view
add locale field for exams
Use the locale field to set interface language for exams
Make exam.locale field temporarily non-editable

Until there is something in the front end to allow setting it.  Exams
were not saving otherwise.
Remove exam.locale non-editable restriction
Wrap ExamCopyView url with login_required()

Fixes #133.
don't show copy button in exam/question index page if the user isn't logged in

Thanks to #133
exam pass percentage is off by default

fixes #127
search boxes only search when you press enter or click the button

For #128
Keypresses were getting lost when rendering search results locked the browser up rendering MathJax.
Simplest solution is not to find-as-you-type, and instead only submit the search when you press enter or click on the button.
add "Exams using this question" list to question edit page
add 'progress' field for questions

The 'progress' field should be used to mark questions as ready for use, being written, not to be used by others, etc.
I'd like some input on the available choices. At the moment they are:
-Writing in progress
-Not for general use
-Undergoing testing
-Tested and ready to use
Should they be per-server options?
question progress values have hyphens instead of spaces

In case I want to use them as css class names later
show question authoring progress in search on exam edit page
resubmit search when 'mine' checkbox changes
update migration to progress field with new default

default is now 'in-progress' instead of 'in progress'
move progress selector to top row of question edit