The recent change to cast bool config vars as ints to handle a '0' or
'1' value was shortsighted, since it doesn't allow for instances where
the variable is set to an empty value (or '' or any invalid/non-int
value).
This introduces a read_config_bool method for reading values that should
be a '0' or '1', but will default to False if not a digit (otherwise the
value will be cast as bool(int(value)) if "value" is a digit str).
Fixes#288
d2fac809ca