Gromox 2.21

Fixes:

• exch: fix nonsensical compare operation in function check_message_owner
• lib: guard against an integer overflow when inserting last element in range_set
• imap: do not flag zero-length usernames/passwords as a syntax error
• exmdb: avoid showing E-5310/5311 for absent files

Enhancements:

• Support for outgoing message submission via postdrop. Use the new config directive outgoing_smtp_url=sendmail://localhost in gromox.cfg.
• gromox-snapshot: Support snapshots on XFS
• zcore: log REMOTE_ADDR on authentication failure for fail2ban
• ews: improve contact item and task item support
• php-mapi: add mapi_getuserfreebusyical function
• exmdb: add ICS request dumper (config directive gromox.cfg:exmdb_ics_log_file)

Behavioral changes:

• kdb2mt: remove option aliases that have been deprecated for a year