NodeList returns : add "abstract_mem.h" to NodeList/*.c files so that the code could compile.
	You can now run "cmake -DUSE_NODELIST=ON <src>", compilation won't fail.
Nodelist returns: adds file nodelist_avl.c to git and to files listed in CMakeLists.txt .
	This is an empty file for now. It will contains a function to turn a nodelist into a tree of IP address.
NodeList returns: 1st pass of checkpatch on source. More will follow.