config/option-parser: Bools are bool
I finally got annoyed enough to do this.
config_parser_get_bool actually work on bool types, and also make option-parser's
WESTON_OPTION_BOOLEAN also work on bools.
This allows us to remove a bunch of pointless shadow variables: we'd have a local int to pass to config-parser and/or option-parser, then assign it to a longer-lived bool.