- the serve.py is now only the interface, everything goes through App class.
- implemented an /admin page to authorize students and reset passwords. this is done with a webservice that responds to AJAX.

test:
- check if questions exist when building testfactory
- final grade is rounded to 1 decimal place (0.0 - 20.0)
questions:
- added support for correction comments for textarea type questions.
- scripts can return grade or a dictionary {grade: 10.0, comments:'hello'}
serve:
- implemented a werbservice for /admin
- moved authentication requirements into the serve.py
- tried to improve security (but webservices still missing)
- templates are obtained only once
regressions:
- configuration is a completle mess