add config name to .img or .iso
make all now makes build/(ARCH)/
(CONFIG_NAME)_harddrive.img, where CONFIG_NAME is desktop, server, demo, etc., matching the basename of FILESYSTEM_CONFIG.
./build.sh gives options so you don't have to type make ARCH=arch CONFIG=config FILESYSTEM_CONFIG=config/arch/config.toml target
./build.sh --help for details.