please update .cvsignore

[Jun T. <tak...@kb...>]

[1] Please consider the attached patch for .cvsignore's.

If BeOS is still supported, please add src/beos/.cvsignore also
(I guess only 'Makefile' need be listed in the file).

[2] docs/pdffigures.tex is created by 'make' and removed by
'make clean'. So I think it need not be tracked by CVS.