Removed any traces of logback. 

There should be no dependency to any logging implementation.

Change-Id: I344fd8175b2aad16da82c52c336ec50101652fd9
Signed-off-by: Roozbeh Farahbod <roozbeh.farahbod@sap.com>
Merge pull request #102 from roozbehf/master

Removed any traces of logback.