make pack_tv,pacK_system configurable
liram/pack_tv: change config file location
liram-manage: comment
liram/pack_tv.sh: restore env vars

restore PACK_ROOT, PACK_COMPRESS_FORMAT, IMAGE_DIR from env after loading the
config file
config files for liram, pack_system
scripts/lib/pack_system: catch empty '@'
lib/die_extended: fix comment
lib/function/defined.bash: add call_if_defined()
lib/function/functrace: advertise functrace
lib/logging.sh, dolog(): accept "-n"
lib/message.sh: add no-newline message functions
lib/devel/configure: misc functions for configure scripts