Update SLF4J to 1.7.20
Update SLF4J to 1.7.20

apache/wicket,apache/wicket,dashorst/wicket,mosoft521/wicket,aldaris/wicket,selckin/wicket,AlienQueen/wicket,AlienQueen/wicket,AlienQueen/wicket,aldaris/wicket,bitstorm/wicket,aldaris/wicket,apache/wicket,mosoft521/wicket,aldaris/wicket,apache/wicket,klopfdreh/wicket,mosoft521/wicket,dashorst/wicket,dashorst/wicket,aldaris/wicket,dashorst/wicket,bitstorm/wicket,klopfdreh/wicket,selckin/wicket,apache/wicket,bitstorm/wicket,selckin/wicket,klopfdreh/wicket,selckin/wicket,mosoft521/wicket,AlienQueen/wicket,selckin/wicket,bitstorm/wicket,AlienQueen/wicket,mosoft521/wicket,klopfdreh/wicket,bitstorm/wicket,dashorst/wicket,klopfdreh/wicket