log_level default to zero in interactive mode
log_level default to zero in interactive mode

By default set log_level to 0 in interactive mode, to prevent all
spuriour output. Gets modified accordingly by --verbose or
--veryverbose.

bdurrow/design-center,bdurrow/design-center,tzz/design-center,tzz/design-center,bdurrow/design-center,bdurrow/design-center,tzz/design-center,tzz/design-center