[devtools] fix a couple issues with xvfb-run xvfb-run didn't quite clean up correctly after itself, because: - dash doesn't run EXIT traps on signals - if we don't run the command in the background, a TERM handler doesn't run until the command exits

addressbook
basket
blog
book
calendar
comment
company
email
file
folder
i18ncontent
keyword
link
mailinglist
person
tag
timeseries
vcsfile