[#4859] Update copyright to 2011 in every source file

sflphone-client-gnome/src/accountlist.c

sflphone-client-gnome/src/accountlist.h

sflphone-client-gnome/src/actions.c

sflphone-client-gnome/src/actions.h

sflphone-client-gnome/src/callable_obj.c

sflphone-client-gnome/src/callable_obj.h

sflphone-client-gnome/src/codeclist.c

sflphone-client-gnome/src/codeclist.h

sflphone-client-gnome/src/conference_obj.c

sflphone-client-gnome/src/conference_obj.h

sflphone-client-gnome/src/config/accountconfigdialog.c

sflphone-client-gnome/src/config/accountconfigdialog.h

sflphone-client-gnome/src/config/accountlistconfigdialog.c

sflphone-client-gnome/src/config/accountlistconfigdialog.h

sflphone-client-gnome/src/config/addressbook-config.c

sflphone-client-gnome/src/config/addressbook-config.h

sflphone-client-gnome/src/config/assistant.c

sflphone-client-gnome/src/config/assistant.h

sflphone-client-gnome/src/config/audioconf.c

sflphone-client-gnome/src/config/audioconf.h