Two modifications: 1. The addition of 2013 to the copyright year range for every file; 2. The use of a single year range, instead of potentially multiple year ranges, as approved by the FSF.
gdb/testsuite/ChangeLog: * gdb.base/ctxobj-f.c, gdb.base/ctxobj-m.c, gdb.base/ctxobj-v.c, gdb.base/ctxobj.exp: New files.