[logback-dev] helpful to warn when not configured?

[Roger Pack]

It might be helpful to, if no logback configuration files are found at
runtime, output something mentioning it, like a warning:

"logback: no configuration files found, defaulting to
BasicConfigurator DEBUG level to STDOUT"

As it is sometimes you get DEBUG logs showing up on the screen and
have no idea what's occurring...or what's misconfigured.

Thanks!
-roger-