Change of Logging Framework to SLF4j

I have updated the pom.xml and changed the code to migrate the logging framework from Java util logging to SLF4j. The SLF4j framework supports bridges for other common logging frameworks like java util logging, log4j and also supports creation of custom loggers, and with that would support other people using this library to integrate the log output with the logging framework of their choice. 

More details on http://www.slf4j.org/