copyright years updated on 7.4 branch

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

I realized yesterday evening that gdb-7.4 should at least say
2012 in the version output (same for GDBserver), so I imported
that patch.  And then, thinking it over, I just thought that
it would be simpler for everyone if I also udpated the copyright
notices everywhere.  So I ended up importing the following
changes from HEAD...

 (1/5) gdb/gdbserver/gdbreplay: Update copyright year in version out
 (2/5) Update the copyright header of various files...
 (3/5) more copyright notice reformatting.
 (4/5) [README] Add note about copyright and license notices

... and then re-running HEAD's copyright.py on the 7.4 checkout.
This is:

 (5/5) Copyright year update in most files of the GDB Project.

The last patch was inspected visually again, checking changes
for each file extension separately. And the whole patch series
was also tested on x86_64-linux.

As the time of this writing, the "cvs ci" is still going, but
should terminate soon.