Updated CHANGELOG.md.
Added tag textadept_7.0 for changeset 62229bed720e
Added links to order the book and make donations.
Link to the book's Table of Contents.
New ANSI C lexer.
C/C++ lexer was separated into ANSI C and C++ lexers.
Also took the opportunity to use shorter macros in compile/run commands.

--HG--
rename : modules/cpp/api => modules/ansi_c/api
rename : modules/cpp/init.lua => modules/ansi_c/init.lua
rename : modules/cpp/lua_api => modules/ansi_c/lua_api
rename : modules/cpp/tags => modules/ansi_c/tags
Added support for tabs.