#18 stx:message extension

[Petr Cimprich]

It was suggested to extend <stx:message> with an optional
level attribute: level="trace | debug | info | warn |
error | fatal"?
Meaning: message to an implementation-dependent logging
facility.
Choosing a logging level is also
implementation-dependent (for example
a command-line switch or an API call).
Without level attribute: current meaning.

[http://archive.gingerall.cz/archives/public/stx2003/msg00416.html]