Ahaggar: add an example of the AST dump on kernel/init/main.c

This is the output produced by libahaggar_ast.so on:
Linux next-20130624
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/init/main.c

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Ahaggar: add small notes on the libahaggar_ast library

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>