Release 0.7.0.

Release 0.7.0.

* Use HTTP protocol for all operatiosn
* Webui worker is now removed and controller works as webui
* Allow to serve static files via controller by option `static_dir`
* Rspamd interface is now a part of rspamd
* Rspamc client has been rewritten to use HTTP and non-blocking mode
allowing to start multiple operations simultaneously (see `-n` option)
* Lua API was completely reworked to satisfy modern standards of LUA:
    * Module `lua-message` was removed
    * Reduced number of superglobals registered by rspamd
    * Many functions has been redesigned
    * Symbols registration is now more convenient
* Users settings has been rewritten as lua plugin
* Reworked headers system as gmime's based one misses many headers and is
very slow to get headers values
* Reorganized code and removed embedded jannsson by using UCL for all json
parsing
* Migrated to `librdns` for DNS resolving that improves concurrency for
DNS requests significantly
* Fixed tonns of bugs in MIME processing
* Improved metrcis and default symbol's weights
* Added new RBL's
* Fixed a number of issues in the modules
* Removed several memory leaks found
* Fix unicode processing
* Fix fuzzy checking for unicode parts
* Significantly improve documentation and especially LUA API docs
* See migration notes at https://rspamd.com/doc/migration.html

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