Rename tools/ directory to scripts/ directory.

It's common for other projects (eg, QEMU, Linux) to put build scripts
into a "scripts/" directory.  There's no reason for SeaBIOS to be
different, so rename the "tools/" directory to "scripts/".

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Update kconfig to latest version.

Update kconfig (from Linux v2.6.38-rc2) to the latest version (from
Linux v3.11-rc6).

This is a copy of kconfig from Linux with only the changes necessary
to work with the SeaBIOS build (the equivalent of the earlier SeaBIOS
0da7bfdf commit) and the changes necessary to always emit symbols
(SeaBIOS b623e7c5 commit).

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>