Fix Diaspora outgoing implicit mention
Fix Diaspora outgoing implicit mention

- Use name instead of nick for implicit mention
- Rename $parent to $toplevel_item in Diaspora::constructComment
- Use thread parent to retrieve the expected mention instead of the top level item

tobiasd/friendica,fabrixxm/friendica,annando/friendica,annando/friendica,annando/friendica,tobiasd/friendica,fabrixxm/friendica,friendica/friendica,tobiasd/friendica,fabrixxm/friendica,friendica/friendica,friendica/friendica,friendica/friendica,tobiasd/friendica,fabrixxm/friendica,fabrixxm/friendica,friendica/friendica,annando/friendica,annando/friendica,tobiasd/friendica