New cbfstool. Works without mmap or fork/exec and

New cbfstool. Works without mmap or fork/exec and
supports fixed location files. Some parts are salvaged
from the pre-commit version (esp. stage and payload creation),
others are completely rewritten (eg. the main loop that handles
file addition)

Also adapt newconfig (we don't need cbfs/tools anymore) and fix
some minor issues in the cbfstool-README.

Signed-off-by: Patrick Georgi <patrick.georgi@coresystems.de>
Acked-by: Stefan Reinauer <stepan@coresystems.de>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@4630 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1