* Fix stat_cache closing
* Add checkpoints to sqlite3 learn cache
* Do not recompile lua generated headers all the time
* Increase number of messages learned
* Fix issues with dual stack and hfilter
* Disable MID checks for hfilter by default
* Fix cache definitions in multiple classifier and no type
* Don't crash if learn cache failed to initialize
* Fix googlegroups support in maillist plugin
* Rework flags LUA API:
	- Allow to check for a specific flag
	- Add `learn_spam`, `learn_ham` and `broken_headers` flags
	- Unify internal functions
* Add `BROKEN_HEADERS` rule
* Add support for forged confirmation headers (by @AdUser)
* Allow `any`, `mime` and `smtp` for get_from/get_recipients
* Add mime types checking plugin
* Add rule to detect spammers attempts to cheat mime parsing
* Rework parsing of IP addresses in configuration (better IPv6 support)
* Add `util.parse_mail_address` function to LUA API
* Add lua sqlite3 module
* Implement synchronous redis call
* Ratelimit: avoid possible indexing of nil value (Fixes #498) (by @fatalbanana)
* Add stat_convert command to convert stats tokens from sqlite3 to redis
* Implement redis advanced lua api with pipelining
* Fix memory leak on redis stat (#500)
* Fix user/language learn count in sqlite statistics (#496) (by @fatalbanana)
* Fix build with custom pcre
* Fix fuzzy relearning (#498)
* Improve planning of asynchronous tasks
* Show slow rules in log
* Add warning for slow regexps
* Add base32 decode/encode routines to lua util
* Allow converting of learn cache from sqlite to redis
* Add methods to check if a messages has from/rcpts
* Improve and fix multimap plugin:
	- Restore 'header' maps
	- Add filters for headers
	- Add 'email:addr', 'email:user', 'email:domain' and 'email:name' filters
	- Add generic regexp filters
* Disable reload command in rc scripts
* Improve runtime CPU dispatcher for libcryptobox
* Add preliminary support of digital signatures via ed25519
* Add detection for RDRAND support
* Print configuration of crypto on start
* A in SPF presumes AAAA lookup as well

Signed-off-by: Vsevolod Stakhov <vsevolod@highsecure.ru>

- Restore 'header' maps
- Add filters for headers
- Add 'email:addr', 'email:user', 'email:domain' and 'email:name'
  filters
- Add generic regexp filters

Issue: #496