If neither whitelist nor blacklist is set, drop all args
Remove superflous comment in default config
conf: add a git section
conf: add check as a whitelisted make target
Fork before calling festival

The voice output takes a while to finish and we don't want to hang the
terminal for however long it takes. So fork, call festival from the child and
exit the parent in the meantime

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>