simplified ImportDialog by using ButtonGroup instead of explicit actionPerformed hooks
simplified ImportDialog by using ButtonGroup instead of explicit actionPerformed hooks

Braunch/jabref,bartsch-dev/jabref,mredaelli/jabref,Siedlerchr/jabref,mairdl/jabref,mairdl/jabref,tobiasdiez/jabref,bartsch-dev/jabref,ayanai1/jabref,jhshinn/jabref,Braunch/jabref,jhshinn/jabref,shitikanth/jabref,Mr-DLib/jabref,zellerdev/jabref,JabRef/jabref,tschechlovdev/jabref,grimes2/jabref,oscargus/jabref,obraliar/jabref,shitikanth/jabref,mairdl/jabref,bartsch-dev/jabref,grimes2/jabref,mairdl/jabref,shitikanth/jabref,oscargus/jabref,motokito/jabref,ayanai1/jabref,sauliusg/jabref,Braunch/jabref,Mr-DLib/jabref,jhshinn/jabref,motokito/jabref,ayanai1/jabref,oscargus/jabref,mairdl/jabref,tschechlovdev/jabref,motokito/jabref,sauliusg/jabref,obraliar/jabref,shitikanth/jabref,mredaelli/jabref,obraliar/jabref,zellerdev/jabref,obraliar/jabref,zellerdev/jabref,shitikanth/jabref,Siedlerchr/jabref,mredaelli/jabref,oscargus/jabref,Braunch/jabref,Mr-DLib/jabref,oscargus/jabref,Siedlerchr/jabref,tobiasdiez/jabref,tschechlovdev/jabref,JabRef/jabref,grimes2/jabref,mredaelli/jabref,Mr-DLib/jabref,grimes2/jabref,sauliusg/jabref,jhshinn/jabref,bartsch-dev/jabref,Braunch/jabref,JabRef/jabref,JabRef/jabref,bartsch-dev/jabref,tobiasdiez/jabref,tschechlovdev/jabref,Mr-DLib/jabref,mredaelli/jabref,tobiasdiez/jabref,motokito/jabref,zellerdev/jabref,sauliusg/jabref,ayanai1/jabref,tschechlovdev/jabref,motokito/jabref,grimes2/jabref,zellerdev/jabref,Siedlerchr/jabref,obraliar/jabref,ayanai1/jabref,jhshinn/jabref