Add missing XMLUnit library to external libs
Add missing XMLUnit library to external libs

Siedlerchr/jabref,JabRef/jabref,oscargus/jabref,zellerdev/jabref,zellerdev/jabref,zellerdev/jabref,shitikanth/jabref,oscargus/jabref,Siedlerchr/jabref,sauliusg/jabref,tobiasdiez/jabref,sauliusg/jabref,sauliusg/jabref,shitikanth/jabref,oscargus/jabref,shitikanth/jabref,jhshinn/jabref,JabRef/jabref,oscargus/jabref,sauliusg/jabref,tobiasdiez/jabref,shitikanth/jabref,tobiasdiez/jabref,zellerdev/jabref,Siedlerchr/jabref,tobiasdiez/jabref,Siedlerchr/jabref,JabRef/jabref,jhshinn/jabref,shitikanth/jabref,JabRef/jabref,oscargus/jabref,zellerdev/jabref,jhshinn/jabref,jhshinn/jabref,jhshinn/jabref