merge of ticket #176 (python logging framework), also changes xfrout to use the python logging.
[func] jerry Added python logging framework. It is for testing and experimenting with logging ideas. Currently, it supports three channels(file, syslog and stderr) and five levels(debug, info, warning, error and critical). git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@2338 e5f2f494-b856-4b98-b285-d166d9295462