Fixes #2159; this is done by force-reloading the handlers to match the
config.
This can create a bit of a funny effect if sys.config specifies an INFO
log level (or lower) is specified. While apps are booted for config
changes before the cth_failonly hook is enabled, supervision and other
application log messages can start being output. They will start being
suppressed once the CT run begins.
This is not a bug, it's a race in instantiation of control and enabling
of log levels. Nothing we can do about that. It might however surprise
people a good bit. If non-default stdout handlers are added, they are
similarly likely to become noisy; specifying a test-specific sys.config
file may be necessary then.
Also includes a bump of cth_readable version, which now checks for
updates to the log formatter on every test output.