Be more explicit about the need for lektord to be launched before using
the lkt client.

Also update the readme:
- add the update procedure
- 80 col formated text

- Add the cli header lib for that client
- Drop in a clang-format file
- Basic luka.cpp

Don't support delete a range of kara in the queue, just a position.

NOTE: Still need to add the module function "set_position(int)" in the
sdl2 player module.