Refactoring test cases in relation to LBCLASSIC-83.

 LBCLASSIC-83 (Logger.setLevel(null) may throw an NPE)

 LBCLASSIC-61 (configurable ObjectName)
 LBCLASSIC-24 (better error messages after reload)
 LBCLASSIC-33 (JMX configurator unregisters itself)
 LBCLASSIC-78 (NPE in JMXConfigurator getLoggerLevel)
 LBCLASSIC-79 (NPE in JMXConfigurator setLoggerLevel)
 

While testing LBCLASSIC 61,24 and 33, I wanted to correct LBCLASSIC-78
and LBCLASSIC-79 which are related to JMXConfigurator. It turns out
that LBCLASSIC-79 has a much deeper cause identified in LBCLASSIC-83.

Work on LBCLASSIC 61,24 and 33 is still ongoing. The present commit
reflects the nature of that ongoing and incomplete work.

This commit is related to:

 LBCLASSIC-61 (configurable ObjectName)
 LBCLASSIC-24 (better error messages after reload)
 LBCLASSIC-33 (JMX configurator unregisters itself)

- Refactoring of LoggerContext class so it has a cleaner lifecycle
- Major refactorization of c.q.l.c.jmx.Configurator (renamed as JMXConfigurator) in order
  to fix the aforementioned bugs
  
  More updates to follow

run on older JDKs we make JDK 1.6 a requirement for running the DBAppenderIntegration tests.

run on older JDKs we make JDK 1.6 a requirement for running the DBAppenderIntegration tests. 

We now use sqljdbc4. (note the suffix 4)

loop len of 10'000 is already pretty long

Related to LBCLASSIC-54

Mopping up refactoring of turbo filters

 	 
- Heavy refactoring of TurboFilters 
  TurboFilters are now collected in a CopyOnWriteArrayList which is
  ensures safe access even if the turbo filter list is modified during
  the lifetime of the application
  
  Added test cases to ensure that performance does not degrade in an
  uncontrolled fashion
  
  More cleaning up to follow

  between successive runs

- added a performance test on LoggingEvent serialization

Lazy initialization of formattedMessage as suggested in LBCLASSIC-47

Fixes LBCLASSIC-49

The getLogger() method in LoggerContext class will now throw an
IllegalArgumentException when invoked with a null argument.
  

- fixed LBCORE-21, 

  TimeBasedRollingPolicy will now check at initialization time
  to see if an existing target file needs to be rolled over
  
- further refactoring of TimebasedRollingPolicyTest

The writer field in WriterAppender has been marked as private, as suggested by Anders Hammar in LBCORE-34

Making BasicStatusManager more sub-class friendly

Added a setter for the StatusManager.

- copyright notices

- documentation on status listeners