[Dovecot] rc29 and documentation changes

http://dovecot.org/nightly/dovecot-latest.tar.gz

Any comments about the doc/wiki/ contents? doc/documentation.txt? dovecot-example.conf's doc/wiki/ pointers?

./autogen.sh now updates the wiki from http://www.dovecot.org/tmp/wiki-export.tar.gz (updated each night) if doc/wiki/Authentication.txt doesn't exist.

I guess I'll release rc29 tomorrow. The current changes are:

+ Added auth_gssapi_hostname setting.
- IMAP: LIST "" "" didn't return anything if there didn't exist a
  namespace with empty prefix. This broke some clients.
- If Dovecot is tried to be started when it's already running, don't
  delete existing auth sockets and break the running Dovecot
- If deliver failed too early it still returned exit code 89 instead
  of EX_TEMPFAIL.
- deliver: INBOX fallbacking with -n parameter wasn't working.
- passdb passwd and shadow couldn't be used as master or deny databases
- IDLE: inotify didn't notice changes in mbox file
- If index file directory couldn't be created, disable indexes instead
  of failing to open the mailbox.
- Several other minor fixes