#183 JBossMX default logging

[Adrian Brock]

The default logging factory for JBossMX can now
be specified using the system property
ServerConstants.LOGGER_FACTORY_CLASS_PROPERTY
or
"jbossmx.logging.adapter.factory.class"

The default is now log4j.

When the factory cannot be instantiated,
e.g. log4j is not available
it will revert to the previous default of System.err
logging.
This is done quietly so that standalone jbossmx
users do not get a nasty ClassNotFoundException
when they don't want to use log4j.

Regards,
Adrian