Extend README with Spirit versions info [skip ci]

README.md

@@ -1,4 +1,4 @@
-spirit
+Spirit
 ======
 
 Spirit is a set of C++ libraries for parsing and output generation implemented as 
@@ -7,3 +7,58 @@ Meta-Programming. The Spirit libraries enable a target grammar to be written
 exclusively in C++. Inline grammar specifications can mix freely with other 
 C++ code and, thanks to the generative power of C++ templates, are immediately 
 executable.
+
+### Spirit.X3 (3rd generation)
+
+[Documentation](http://www.boost.org/doc/libs/develop/libs/spirit/doc/x3/html/index.html)
+
+The newest Spirit shines faster compile times. Currently only a parser framework.
+
+Requires C++14 compiler (GCC 5, Clang 3.5, VS 2015 Update 3).
+
+### Spirit V2 (2nd generation)
+
+[Documentation](http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/index.html)
+
+The latest Long Term Support version of Spirit. A Swiss Army knife for data
+manipulation on any kind of input.
+
+Consists of:
+  - [Qi]: Parser framework.
+  - [Karma]: Generator framework.
+  - [Lex]: Lexical analyzer framework.
+  
+Runs on most C++03 compilers (GCC 4.1, Clang 3.0, VS 2005).
+
+[Spirit V2]: http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/index.html
+[Qi]: http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/spirit/qi.html
+[Karma]: http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/spirit/karma.html
+[Lex]: http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/spirit/lex.html
+
+### Spirit.Classic (1st generation)
+
+[Documentation](http://www.boost.org/doc/libs/develop/libs/spirit/classic/index.html)
+
+An elderling member of Spirit. It receives only limited maintanance, but
+it is still used even inside Boost by [Boost.Serialization] and [Boost.Wave]
+libraries. It also contains Phoenix V1.
+
+Spririt.Classic should support even ancient compilers.
+
+[Boost.Serialization]: http://boost.org/libs/serialization
+[Boost.Wave]: http://boost.org/libs/wave
+
+## Brief History
+
+Date       | Boost | Commit   | Event
+---------- | ----- | -------- | -----------------------------------------------
+2014-03-18 | 1.56  | 8a353328 | Spirit.X3 is added
+2013-12-14 | 1.56  | c0537c82 | Phoenix V2 is retired
+2011-03-28 | 1.47  | 400a764d | [Phoenix V3] support added to Spirit V2
+2009-04-30 | 1.41  | 5963a395 | [Spirit.Repository] is appeared
+2008-04-13 | 1.36  | ffd0cc10 | Spirit V2 (Qi, Karma, Lex, Phoenix V2) is added
+2006-08-23 | 1.35  | 2dc892b4 | Fusion V1 is retired
+2003-01-31 | 1.30  | 81907916 | Spirit is the part of the Boost
+
+[Phoenix V3]: http://boost.org/libs/phoenix
+[Spirit.Repository]: http://www.boost.org/doc/libs/develop/libs/spirit/doc/html/spirit/repository.html