add javadoc, remove redundant constructor fields
add javadoc, remove redundant constructor fields

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