Subject Logging
Author Blas Rodriguez Somoza

I have commited some changes in logging.

Now the default for FBManagedConnectionFactory, FBManager and tests are true and false for other classes.

The method to decide if logging is used depends on the first class with logging used in the driver. Logging or not is managed by
a static variable in LoggingFactory that is only changed the first time that logging is requested. If the log4j classes is not in
the classpath logging is disabled

Default can be changed through the use of the environment variable FBLog4j setting it to "true" or "false" before the driver is
used. In the future will be nice if the change can be do with parameters, but for the first time it is easier to do this way.

Until now logging only can be selected/deselected including or excluding log4j from the classpath, and now it can be choosed
without the need to change the classpath.

Blas Rodriguez Somoza