Adding support for python2.6

NullHandler was introduced in logging module from 2.7 on so we need to
implement this ourselves for 2.6 as documented in
https://docs.python.org/2.6/library/logging.html#configuring-logging-for-a-library
Merge pull request #1 from Jimdo/add2.6support

Adding support for python2.6
Merge pull request #3 from Jimdo/master

Adding support for Python2.6