new logging facilities

[Owen O'Malley]

With the new log4j logging stuff, the way that you set finer grain 
logging levels for particular loggers is via the conf/log4j.properties. 
For example, in mine I have set the level up on 3 classes via:

# Logging levels
log4j.logger.org.apache.hadoop.ipc.RPC=DEBUG
log4j.logger.org.apache.hadoop.mapred.JobTracker=DEBUG
log4j.logger.org.apache.hadoop.mapred.TaskTracker=DEBUG
-- Owen