fixed a few bugs in DS store, now it's somewhat about able to reply to 'GET foo' with a bogus value.

cron part of disk store object cache implemented. Objects are pushed as IO jobs if needed, so that the IO thread will process them.

touched key for WATCH refactored into a more general thing that can be used also for the cache system. Some more changes towards diskstore working.

Raw output mode is selected by default when STDOUT is not a tty. For
ttys, raw output can be forced using the option "--raw".