FSF address incorrect in COPYING

[pypingou]

In the COPYING file the address of the FSF is no long correct.

The new address is:
Free Software Foundation
51 Franklin Street, Fifth Floor
Boston, MA 02110-1301
USA
Source: http://www.fsf.org/about/contact/

New GPLv2 file: http://www.gnu.org/licenses/gpl-2.0.txt

Note that version 3 of the GPL does not contain this information any-more, I guess to prevent this situation in the future.
See: http://www.gnu.org/licenses/gpl-3.0.txt

[jdavid]

Fixed, thanks