vfs and initrd (probably buggy... read on)

VFS: Basic implementation of the virtaul filesystem (not really being
used execpt by initrd).

        inc/fs/vfs.h
                struct and interface definition

        fs/vfs.c
                implementation (mostly wrapper functions)

initrd: Initial ramdisk. A way to load user programs into memory without
a disk! Woohoo!

        inc/fs/initrd.h
                filesystem definition

        fs/initrd.c
                basic ramdisk parsing and initialization (no
                read/write/open/readdir/.../etc yet)

        tools/initrd/create
                C utility (PROBABLY BUGGY) to create
                a ramdisk from the binaries loaded in user/bin/

                FIXME: right now this utility only creates the file
                headers, it does not load the file data!!