[OTR] auto-start and require options
let's do it like in pidgin imo it makes most sense, global options:
[x] enable OTR
[x] auto start OTR
[ ] require OTR
[ ] do not log when in OTR
and then allow to override this for each contact.
At least the global require OTR option is quite important for people that want to keep privacy, so easy to forget to click OTR-Start manually each time.