core: overlong UTF-8 encoding and surrogates (U+D800-DFFF) are invalid.
core: move main() function into Curses GUI
core: do not exit WeeChat in weechat_end() (let the caller do that)

This is needed for automated tests, to exit with return code of tests.
core: move some detections from src/CMakeLists.txt to root CMakeLists.txt
tests: add unit tests using CppUTest

The tests can be run only via CMake:

  1. build with tests: cmake .. -DENABLE_TESTS=ON
  2. make
  3. ctest  (or ctest -V for verbose output)
core: update ChangeLog
doc: remove obsolete "test" directory with weercd in developer's guide
core: update translations
Merge branch 'master' of git://github.com/anders/weechat into anders-master
core: fix code style in function utf8_is_valid()
tests: add UTF-8 tests (check of some invalid UTF-8 chars)
core: update ChangeLog
core: add contributor in AUTHORS.asciidoc
core: fix link errors with ncurses library
core: add main.c in list of translated files for gettext
doc: add file main.c in developer's guide
doc: add C++ compiler in dependencies to run tests (user's guide)
core: fix build with autotools (add main.c)
core: remove whitespace in cmake files
core: add build with autotools for Travis CI