Switch sources over to use the GPL version 3

bfd/COPYING

bfd/ChangeLog

bfd/aix386-core.c

bfd/aix5ppc-core.c

bfd/aout-adobe.c

bfd/aout-arm.c

bfd/aout-cris.c

bfd/aout-ns32k.c

bfd/aout-sparcle.c

bfd/aout-target.h

bfd/aout-tic30.c

bfd/aout0.c

bfd/aout32.c

bfd/aout64.c

bfd/aoutf1.h

bfd/aoutx.h

bfd/archive.c

bfd/archive64.c

bfd/archures.c

bfd/armnetbsd.c