change sandbox to use lxc-execute

lxc-execute is a better fit for application containers
judging now works!
local settings for dev env
nginx + uwsgi combo works
add judge data to fixtures. fix uwsgi setup. fix judge.
final polishes
start uwsgi only on vagrant-mount
oops
broken json
do not repeat my mistake!
celery directories
tab to spaces
create user
oops... tabs