Release 0.9.0

Release 0.9.0

* Add support of the fast and secure protocol level encryption:
	- curve25519 is used for key exchange;
	- chacha20/poly1305 cryptobox construction for bulk encryption;
	- zero latency overhead;
	- encrypting and balancing HTTP proxy worker
* Rework expressions and create new expressions library:
	- aggressive optimizations based on the abstract syntax tree;
	- abstract expressions support (regular expressions, functions, lua modules
		composites and so on)
	- New comparision and '+' operators support
	- New greedy algorithm to minimize execution time of expressions and
		all symbols
	- Dynamic expressions benchmark and reoptimizations
* Many improvements to the LUA API:
	- reworked logger module allowing to do pretty print of the most of lua
		types (including tables and userdata classes)
	- reworked lua redis and lua HTTP to support more features
	- added opaque type for passing large text chunks without copying
	- new regexp module with many auxiliary functions (e.g. `re:split`)
* LuaJIT is now the default requirement for rspamd allowing to speed up lua
	execution by a large margin (however, plain lua is still supported)
* New plugins:
	- spamassassin rules plugin that allows to load and re-use the most of
		SA rules natively
	- DMARC plugin that evaluates SPF and DKIM policies to the domain policies
	- many old plugins has been reworked to implement new features and improve
		stability
* New aho-corasic trie implementation from @mischasan that allows to load and
	use hundreds of thousands of patterns with no influence on load
* Support of PCRE JIT and PCRE JIT fast path modes that significantly improves
	the performance of regular expressions if supported by PCRE
* New URLs parser and extractor:
	- removed legacy code that was useless for url finding
	- reworked algorithms of URL parsing for more precise and accurate results
	- added top-level-domains tree from http://publicsuffix.org
	- improved emails parsing
	- removed many phishing false positives due to TLD tree check
* New statistics infrastructure:
	- created a separate layer of statistic library
	- improved OSB-Bayes by re-weighting tokens according to the original
		academic paper and `crm114` implementation, which reduced false positives
		rate significantly
	- created learn cache to avoid double learning of statistics and providing
		an efficient way to re-learn class for a message
	- created abstract layers for different statistics backends
	- implemented new tokenization algorithms with fast or secure (siphash)
		hashes to generate statistics features
* Reworked utf8 tokenization that previously corrupted all UTF8 words (minor
	incompatibility with old fuzzy hashes with utf-8 symbols)
* SPF module has been completely rewritten to support complex cases of
	`include` and `redirect` within SPF records
* DKIM module now supports multiple signatures
* Controller passwords can now be stored encrypted by `PBKDF2-HMAC` in the
	configuration file
* Many hand-written HTTP clients has been replaced with the common rspamd
	http module
* New test framework:
	- import lua `telescope` test framework
	- add unit tests for many rspamd modules and routines
	- create a unit test for each possible bug found
	- use luajit ffi for testing C code
	- added preliminary support of functional testing by creating tasks from lua
* Randomize hash seed to avoid certain hash tables vulnerabilities
* Documentation improvements:
	- added documentation for the vast majority of rspamd modules
	- added documentation for rspamd protocol
	- added documentation for the most of rspamd LUA extensions
* Fixed tonns of bugs and memory leaks
* Added tonns of minor features

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