allow backslashes to escape inside format strings;  walk format code for labels and titles even in xml/json mode to allow fields to be popped off xo_vap
update tests
update tests
update tests
update tests
update tests
update tests
update tests
update tests
update tests
Add +xo_set_options(); make depth check failure return (instead
Add +xo_set_options
need ":" in front of old style options
need ":" in front of old style options
use xo_errx; fix a couple of error messages; give usage message when there is nothing to do