[PATCH] Allow setting use_cache in config file

[Michael E Brown]

Here is a small patch to allow setting config_opts['use_cache'] in the
config file. So you do not have to use --autocache on every cmdline. It
also adds a --nocache option, to override cfg file, if necessary. This
was the original intent, but wasn't tested.

Options are always processed in the config file and overridden by
cmdline args.
--
Michael